Release tooling: Defer version bumping to the publish step - Cherry picking #23393

[JReinhold]

What I did

This PR manually cherry-picks #23393 back tomain so it has an immediate effect. It looked to be working on next, as the prerelease PR only has deferred version bumps: https://github.com/storybookjs/storybook/pull/23414/files#diff-af9b72cb6dcf333969863361a126e03c67fb19ec94a062462e4d4bc3e2f801cb 💪

(this also re-adds CONTRIBUTING/RELEASING.md, I'm not sure why that was ever deleted on main)

Release tooling: Defer version bumping to the publish step

(cherry picked from commit a930066)

How to test

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• If this PR should be tested against many or all sandboxes,
  make sure to add the ci:merged or ci:daily GH label to it.
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "documentation", "maintenance", "dependencies", "other"]