chore: update pom xml and crowd deps

[DuMaM]

Small clean-ups

• update pom xml
• add some docs for contributing
• dropping support for java lower then 11

After this change, I will bump Jenkins core.

Testing done

Manual testing

Submitter checklist

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1. Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
2. Ensure that the pull request title represents the desired changelog entry
3. Please describe what you did
4. Link to relevant issues in GitHub or Jira
5. Link to relevant pull requests, esp. upstream and downstream changes
6. Ensure you have provided tests - that demonstrates feature works or fixes the issue