Document release process

[LlGC-szw]

There is a very minimalistic release process document at https://github.com/UniversalViewer/universalviewer/wiki/Publishing-UV

We should expand upon this (either in the existing location or somewhere else).

We need to determine how we decide when it is time to make a release, who is authorized to publish the release, and what process should be followed to mint the release.