* Add cache for maven local repo.

* FIx formats.

* plugin test with jdk14

* introduce jdk14 container

* remove docker:build

* remove BUILD_NO and introduct image_version

* Update docs/en/guides/Plugin-test.md
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>
Co-authored-by: Nkezhenxu94 <kezhenxu94@apache.org>
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>

1. Re-balance the workload of plugintests
2. Restore testcases of MySQL, remove on #4641
3. Support user to runs plugin-test on debug mode. It will not remove the log files and actualData.yaml
4. remove paramater 'parallel_run_size' and disable parallel test.

Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>
Co-authored-by: Nkezhenxu94 <kezhenxu94@apache.org>