One of the main roles of the AppOrganization docs is to provide
information on the processes through which official apps are added and
removed. Currently this information is spread between multiple places,
which makes it hard to follow.

This commit consolidates the docs on the main processes, so that
AppLifecycle.md contains a complete overview. It does this by:

1. Moving material from ReviewProcedures.md into AppLifecycle.md
2. Adding the incubator expectations from the incubator README [1] to
   AppLifecycle.md (this contentmaterial will need to be removed from
   the README to avoid duplication

[1]
https://gitlab.gnome.org/GNOME/Incubator/Submission/-/blob/main/README.md