Docs: Update extensions docs to clarify release process and audience. #19276
Description
What would you like to be added?
We need to update our extensions docs to properly separate the developer and user audiences, as well as adding some clarity to the release process.
Why is this needed?
Currently, the extensions docs are confusing because they combine materials for developing extensions with materials for using extensions - additionally, the release process isn't properly outlined.
Additional context
No response