Spike: Write a doc about the current customization options

Background

1. We added most customization options in 4.7 and 4.8 and we don't have a summary of what is possible today and what is missing for our two new customization epics.

Acceptance Criteria

1. Write a doc about the current customization options and check the result with Serena.
2. This should include these epics:
   1. ODC-4650 Customization of available roles in Project Membership
   2. ODC-5010 Quick Starts - enhanced capabilities (the hide Quick start part only)
   3. ODC-5013 Add page redesign & Admin configuration (the customization part only)
   4. ODC-5057 Customize dev catalog categories
3. If possible it should contain known issues like
   1. We can hide add page actions, but some other pages still shows links to that

Additional Details:

• Console enhancement docs: https://github.com/openshift/enhancements/tree/master/enhancements/console