MAINT : Moved Docker images repo to docker folder in main branch

[Helion55]

Reference Issues or PRs

Fixes #2871

What does this implement/fix?

Moved docker-images repo back to main nebari's repo. Changes made,

1. Created folder named docker and moved the necessary files from docker repository.
2. Updated the .github/workflows folder by adding the build-push-docker.yaml and test-images.yaml files from docker repo's workflow folder.
3. Added documentation.yml and RFD.md files to .github/ISSUE_TEMPLATE folder.
4. Updated .pre-commit-config.yaml file.

Testing

• Did you test the pull request locally?
  no
• Did you add new tests?
  no

Any other comments?

no

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[Adam-D-Lewis]

Thanks for separating that work into separate PRs @Helion55. Can you get the "pre-commit" check to pass before we review. Thank you!