Nacos standalone mode don't use in-memory storage therefore we don't
need mysql

* restore solrj-plugin

* restore solrj-plugin

* TracingContext optimize

* fix checkstyle

#2886

* Add cluster-etcd-plugin

* Provide Apollo dynamic configuration center implementation. fixes #2825

Add CI scripts for plugin import check.

Typical test benchmark for performance improvement. Check PR for more detail.

/**
     * # JMH version: 1.21
     * # VM version: JDK 1.8.0_111, Java HotSpot(TM) 64-Bit Server VM, 25.111-b14
     * # VM invoker: /Library/Java/JavaVirtualMachines/jdk1.8.0_111.jdk/Contents/Home/jre/bin/java
     * # VM options: -Dfile.encoding=UTF-8
     * # Warmup: 3 iterations, 10 s each
     * # Measurement: 5 iterations, 1000 ms each, 1000 calls per op
     * # Timeout: 10 min per iteration
     * # Threads: 1024 threads, ***WARNING: Synchronize iterations are disabled!***
     * # Benchmark mode: Throughput, ops/time
     * # Benchmark: org.apache.skywalking.apm.commons.datacarrier.common.AtomicRangeIntegerTest.testNewGetAndIncrementPerformance
     *
     * # Run progress: 0.00% complete, ETA 00:01:10
     * # Fork: 1 of 1
     * # Warmup Iteration   1: 2078993549.108 ops/s
     * # Warmup Iteration   2: 6408026002.297 ops/s
     * # Warmup Iteration   3: 5455960135.636 ops/s
     * Iteration   1: 165330.972 ops/s
     * Iteration   2: 95420.526 ops/s
     * Iteration   3: 173340.089 ops/s
     * Iteration   4: 94214.669 ops/s
     * Iteration   5: 261606.088 ops/s
     *
     *
     * Result "org.apache.skywalking.apm.commons.datacarrier.common.AtomicRangeIntegerTest.testNewGetAndIncrementPerformance":
     *   157982.469 ±(99.9%) 265443.465 ops/s [Average]
     *   (min, avg, max) = (94214.669, 157982.469, 261606.088), stdev = 68934.825
     *   CI (99.9%): [≈ 0, 423425.934] (assumes normal distribution)
     *
     *
     * # JMH version: 1.21
     * # VM version: JDK 1.8.0_111, Java HotSpot(TM) 64-Bit Server VM, 25.111-b14
     * # VM invoker: /Library/Java/JavaVirtualMachines/jdk1.8.0_111.jdk/Contents/Home/jre/bin/java
     * # VM options: -Dfile.encoding=UTF-8
     * # Warmup: 3 iterations, 10 s each
     * # Measurement: 5 iterations, 1000 ms each, 1000 calls per op
     * # Timeout: 10 min per iteration
     * # Threads: 1024 threads, ***WARNING: Synchronize iterations are disabled!***
     * # Benchmark mode: Throughput, ops/time
     * # Benchmark: org.apache.skywalking.apm.commons.datacarrier.common.AtomicRangeIntegerTest.testOriGetAndIncrementPerformance
     *
     * # Run progress: 50.00% complete, ETA 00:00:43
     * # Fork: 1 of 1
     * # Warmup Iteration   1: 3345520433.355 ops/s
     * # Warmup Iteration   2: 4823749249.799 ops/s
     * # Warmup Iteration   3: 6676209367.819 ops/s
     * Iteration   1: 34885.954 ops/s
     * Iteration   2: 33128.147 ops/s
     * Iteration   3: 31300.865 ops/s
     * Iteration   4: 19188.602 ops/s
     * Iteration   5: 34664.282 ops/s
     *
     *
     * Result "org.apache.skywalking.apm.commons.datacarrier.common.AtomicRangeIntegerTest.testOriGetAndIncrementPerformance":
     *   30633.570 ±(99.9%) 25249.253 ops/s [Average]
     *   (min, avg, max) = (19188.602, 30633.570, 34885.954), stdev = 6557.151
     *   CI (99.9%): [5384.317, 55882.822] (assumes normal distribution)
     *
     *
     * # Run complete. Total time: 00:01:26
     *
     * REMEMBER: The numbers below are just data. To gain reusable insights, you need to follow up on
     * why the numbers are the way they are. Use profilers (see -prof, -lprof), design factorial
     * experiments, perform baseline and negative tests that provide experimental control, make sure
     * the benchmarking environment is safe on JVM/OS/HW level, ask for reviews from the domain experts.
     * Do not assume the numbers tell you what you want them to tell.
     *
     * Benchmark                                                  Mode  Cnt       Score        Error  Units
     * AtomicRangeIntegerTest.testNewGetAndIncrementPerformance  thrpt    5  157982.469 ± 265443.465  ops/s
     * AtomicRangeIntegerTest.testOriGetAndIncrementPerformance  thrpt    5   30633.570 ±  25249.253  ops/s
     */

* Update backend-alarm.md

* Update backend-alarm.md

* Fix no stream register.

* Make sure list order.

* Refactor codes.

* Fix wrong revert.

* Revert SolrJ plugin.

* Remove an unexpected test case.

* Revert "Remove an unexpected test case."

This reverts commit 359990e18b0c0ae1a6e1005ff985bf237ec05619.

* Clear context.

* Fix a leak.

* Adjust pom plugin position and add docs

* Polishing

* Update as requested

* fix potential NullPointerException

* Revert "fix potential NullPointerException"

This reverts commit 8393656

* fix potential NullPointerException
the static paramater is best to use the class to reference

* Create ES-Server-FAQ.md

* Update README.md

* Update ES-Server-FAQ.md

* Test

* Sync

* Update ITNacosConfigurationTest.java

* Trigger CI

* Trigger CI

* Trigger CI

* Trigger CI

* Trigger CI

* Remove unused imports to fix checkstyle

* Remove unused imports to fix checkstyle

* Increase timeout since nacos starts slowlly

* Bump up Oracle JDK version

* Remove OracleJDK due to license

* Add CI-with-IT profile and openjdk9

* Add missing profiles

* Lift failsafe plugin to root

* Update pom.xml

* Remove OPENJDK9

* Try parallel builds and add agent

* Try parallel build and windows

* Try parallel build and windows

* Try parallel build and windows

* Try parallel build

* Try parallel build

* Try parallel build

* Fix indentation

* Trigger CI

* Trigger CI

* Remove Windows stage

* Update mvnw.cmd

Get the document by index name.

* Optimize code logic

* revert

* fix

Fixed a time series bug about downsampling setting in processors are different from the setting in receivers. (#2856)

#2851

* Improve plugin performance. fix #2837

* Make exporter interface better.

* Fix review.

* Provide Nacos dynamic configuration center implementation. fixes #2816

* Add unit tests

* Sync

* Replace pull-mode with watch-mode

* Fix ci

* Unify dependency management

* Add integration tests

* Revert unexpected changes

* Add more test cases

* Revert unexpected changes

* Suppress IDE warning

* Correctify volumes position

* Add license header

* Remove Chinese comments

* Sync

* Sync

* Sync

* Sync

* Revert unexpected changes

* Rebase on refactored code and add missing config to docker

* Fix unit test

* Revert unnecessary changes

* new branch for solrj-plugin

* rollback and add module solrj-plugin

* preparing to pr

* to resolve reviewers' suggestions

* remove unused code

* remove unused code

* remove unused comments

* To avoid NPE

* fix typo

* Change to JRE6

* fix pom.xml merge incorrectly. and java.net.URL instead of Regex

* Using RuntimeContext instead of ThreadLocal

* To reduce unnecessary tags

* add test cases

* fix validation fail

* add solrj-plugin into component-libraries & Supported-list

* to trace all patch to avoid recheck status of span

* remove unnecessary properites

* remove unnecessary tags

* Add the config to document of setup

* add time series implementation configuration.

* add configuration-api.

* Implement the base of config API module.

* Finish configuration module codebases w/o tests, revert some changes.

* Finish mock tests.

* Add new gRPC service for configuration.

* Make gRPC configuration sync provider works.

* Add database slow statement dynamic setting.

* Finish the dynamic configuration service.

* Fix version.

* The new feature of Elasticsearch storage with the time series implementation.

* Time bucket util improve.

* Fixed some Gramma error.

* Update ttl.md

Polish English a little.

* Update ttl.md

Add more explicit description of TTL

* Update ttl.md

* Update StorageModuleElasticsearchConfig.java

Set otherMetricsDataTTL = 0 as default, make user more clear.

* Rename the timeSeriesAble to capableOfTimeSeries

* Fixed a test case failure.

* fix NPE

* fix 6.x

* optimize

* add final

* fix ci

* Update apm-sniffer/apm-sdk-plugin/jdbc-commons/src/main/java/org/apache/skywalking/apm/plugin/jdbc/JDBCDriverInterceptor.java

add not null
Co-Authored-By: NXin,Zhang <zhangxin@apache.org>