[Feature] Linkis commons module optimization

[peacewong]

What is the purpose of the change

[Feature][Linkis-mybatis] Add connection pool keepalive feature feature [Bug] Linkis Client duplicate try login bug [Bug] HDFS module for FS opened with public user,should not to execute close action bug [Feature][linkis-common] Add custom variables feature [Bug] Scheduler job should support the clear method to reduce memory footprint bug [Bug] bin tar.gz has akka licenses but no akka libs

Related issues/PRs

Related issues: close#5084 close #5098 close #5099 close #5100 close #5101 close #5102

Checklist

• [x] I have read the Contributing Guidelines on pull requests.
• [ ] I have explained the need for this PR and the problem it solves
• [ ] I have explained the changes or the new features added to this PR
• [ ] I have added tests corresponding to this change
• [ ] I have updated the documentation to reflect this change
• [ ] I have verified that this change is backward compatible (If not, please discuss on the Linkis mailing list first)
• [ ] If this is a code change: I have written unit tests to fully verify the new behavior.