* fix #1976
System Topic like SCHEDULE_TOPIC_XXXX should not be create or delete by user

* User can not send message to system topic SCHEDULE_TOPIC_XXXX

* the-->The

* fix magic number 18

* move system topic to TopicValidator except TBW102

* move TBW102 and isSystemTopic to TopicValidator

* add test code

* validateTopic --> validatorSystemTopic, validatorBlacklistTopic

* validateTopic --> validatorSystemTopic, validatorBlacklistTopic

* rename some methods

2. fix properties when store message
3. add IT for transaction
4. correct resonse code when slave down

optimization : change SYNC_MASTER flushSlave/flushDisk to pipeline to reduce produce latency and improve throughput

* Remove the useless files

* Replace PermSize with MetaspaceSize, details see http://openjdk.java.net/jeps/122

* Update DLedgerCommitLog.java (#1145)

Delete useless code

* Remove the duplicate content

* Polish the comment (#1107)

* Minor Typo fix  (#860)

* [ISSUE #1082] Fix disconnection of HA (#1083)

* fixed the text description in chinese doc (#1339)

* fix /dev/shm not found on some OSs (#1345)

* Refactor the protection logic when pulling

* change the MQVersion variable to rocketmq 4.5.2 version;

* Minor polish

* Fix the wrong package name

* [maven-release-plugin] prepare release rocketmq-all-4.5.2

* [maven-release-plugin] prepare for next development iteration

* [RIP-15]Add Ipv6 support for RocketMQ

Delete useless code