Versions, Branches, Releases

[janpio]

This PRs collects and centralizes the existing information on versions, branches and releases.

It builds a unified, generalized release process documentation based on these existing individual different descriptions:

• https://github.com/apache/cordova-coho/blob/master/docs/plugins-release-process.md
• https://github.com/apache/cordova-coho/blob/master/docs/platforms-release-process.md
• https://github.com/apache/cordova-coho/blob/master/docs/tools-release-process.md
• https://github.com/apache/cordova-coho/blob/master/docs/app-hello-world-release-process.md
• https://github.com/apache/cordova-coho/blob/master/docs/coho-release-process.md

It replaces:

• https://github.com/apache/cordova-coho/blob/master/docs/storing-repo-versions-design.md#choosing-version-numbers-based-on-dev-vs-release (only the linked headline and children, "Storing Versions" is taken care of via other PR)
• https://github.com/apache/cordova-coho/blob/master/docs/versioning-and-release-strategy.md