[Pull Request Checks] Migrate pull request checks into a jenkinsfile

[peternied]

Combine gradle precommit and checks into a single workflow. Then switch the jenkins job to use this file so pull request configuration is managed in this repository.

There is also room for improvement as the gradle precommit check can fail and when this happens the more intensive gradle check will also fail and maybe not provide useful results. Maybe there is a way to reduce resource usage or provide faster results.

[dblock]

The Jenkinsfile could live in this repo, too.

[peterzhuamazon]

Before we can resolve the issue where PR builder is able to run on pipeline this is not solvable at this point opensearch-project/opensearch-build#851

[peterzhuamazon]

I dont want to introduce more issues by using precommit to trigger gradle check directly in freestyle.

[minalsha]

Please reopen if this issue still persists. We have public Jenkins now and seems this should have been resolved. Thanks