github management: tweak repo removal language
github management: tweak repo removal language

Added a new case I just ran into, and removed SIG Architecture
from having to be involved in the decision to archive (I view
consulting SIG Arch as part of the process for finding new
active maintainers of the project, we could bake this into the
language if it needs to be explicit)

Formatting changes:
- Trimmed whitespace in the FAQ
- Unindented headers
- FAQ questions are now bold rather than italic
- Repo removal is a checklist to follow

bgrant0607/community,kubernetes/community,pwittrock/community,bgrant0607/community,kubernetes/community,pwittrock/community,kubernetes/community