Avoid pushing branches onto origin and enforce developers to use fork repo for PR's

### Feature Request / Improvement

Suggestion from @jcamachor

(This is not strictly about the release, but it's useful to address as we do housekeeping and establish processes.) Regarding branches, I notice there are many different branches in the main repository. It would be better if the branches in the main repository were only used for releases as described here. It is common for development to be done in branches within users' forks (unless we establish some process for large feature branches), and PRs can be created from there. We can start a separate discussion in the dev list to address this and clean things up.

https://github.com/apache/incubator-xtable/pull/434#discussion_r1668206929

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

Start with the branch guidance referenced in the issue and the discussion on pull request #434. Review the current branches in the main repository and the existing fork-based PR process. Done means the project has an agreed process for development branches, release-only branches are identified, and obsolete branches are cleaned up.

Written by the indexing model from the issue text.