* Remove agent codes and clean up

* Add all agent config to `agent.conf` file for convenient containerization use cases

* Fix name and default value

* Fix kafka-reporter-plugin shade package conflict

Don't shade lz4, snappy or zstd package because they call native library files.

* fix: Fix MultiScopesAnalysisListener#setPublicAttrs log warn frequently. #6562

1. Rename current STATUS_CODE to HTTP_RESPONSE_STATUS_CODE, real tag key should be http.status_code.
2. Add a new string tag RPC_RESPONSE_STATUS_CODE to hold all string type value tag. The key is `rpc.status_code`.
3. At the backend, keep responseCode for HTTP_RESPONSE_STATUS_CODE tag, but add @Deprecated. Also, add httpResponseStatusCode(a duplicate of responseCode) and rpcStatusCode(for RPC_RESPONSE_STATUS_CODE) fields for OAL.

* Modify `Tags.STATUS_CODE` field name to `Tags.HTTP_RESPONSE_STATUS_CODE` and type from `StringTag` to `IntegerTag`, add `Tags.RPC_RESPONSE_STATUS_CODE` field to hold rpc response code value.

* Add `rpcStatusCode` for `rpc.status_code` tag in the OAL objects. The `responseCode` field is marked as deprecated and replaced by `httpResponseStatusCode` field. 

* Tag `status_code` is still supported in the backend for forward compatbility. Will be removed one year later.
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Remove page path in the browser log query condition.

* Remove endpoint name in the backend log query condition.

Support Metric level function `serviceRelation` in `MAL` and binding  envoy metrics into the topology. (#7399)

* Support Metric level function `serviceRelation` in `MAL`.
* Support envoy metrics binding into the topology.
* add istio args
* remove istio 1.7
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>
Co-authored-by: NJared Tan <jian.tan@daocloud.io>
Co-authored-by: NZhenxu <kezhenxu94@apache.org>

* Add Thread and ClassLoader Metrics for the self-observability

* update CHANGES.md

* update OC receiver MAL settings

* Upgrade agent plugin for ElasticJob 3.0.0 GA version.

* Remove 3.0.0 alpha support.

Remove the following plugins due to they are legacy and unstable releases.
1. sharding-jdbc-1.5.x-plugin
2. sharding-sphere-4.x-rc3-plugin
3. sharding-sphere-4.x-plugin (This is for RC1 and RC2)

To people who want to use these removing versions, you still could copy the plugins from SkyWalking's 8.6.0 release to the '/plugins' folder to activate, unless SkyWalking has some core level APIs upgrade. This is very rare to happen.

* Performance: remove the synchronous persistence mechanism from batch ElasticSearch DAO. Because the current enhanced persistent session mechanism, don't require the data queryable immediately after the insert and update anymore.
* Performance: share `flushInterval` setting for both metrics and record data, due to `synchronous persistence mechanism` removed. Record flush interval used to be hardcoded as 10s.
* Remove `syncBulkActions` in ElasticSearch storage option.
* Increase the default bulkActions(env, SW_STORAGE_ES_BULK_ACTIONS) to 5000(from 1000).
* Increase the flush interval of ElasticSearch indices to 15s(from 10s)

Add these 2 references. According to these, **(same _index, _type and _id) in same bulk will be in order**
1. https://github.com/elastic/elasticsearch/issues/50199
2. https://discuss.elastic.co/t/order-of--bulk-request-operations/98124

Notice, the order of different bulks is not guaranteed by the ElasticSearch cluster. We are going to have the risk of dirty write. But consider we set over 20s period between flush, and index flush period is 10, we should be safe.

Recommend 5000 bulk size and 15s flush interval only. The persistent period has been set to 25s.

Groovy naturally supports many dynamic features that we don't benefit for now but cost performance loss, in this patch we compile our Groovy-based DSL scripts statically to optimize performance.

hostInfo.getDatabaseUrl() result in version 8.0.19 or above:

jdbc:mysql:loadbalance://**internally_generated**1620805591623**

hostInfo.getDatabaseUrl() result in version 8.0.18 or below:

jdbc:mysql:replication://127.0.0.1:3306,127.0.0.1:3306,127.0.0.1:3306/mer_goods_admin_sit?useSSL=true&useUnicode=true&autoReconnect=true&rewriteBatchedStatements=TRUE&allowMultiQueries=true&serverTimezone=GMT%2B8