Grouped Space Management features

[kobelb]

Once the Kibana nav is grouped per #53313 #56232, it'd be nice to reflect this grouping within the Spaces Management screens.

[elasticmachine]

Pinging @elastic/kibana-security (Team:Security)

[legrego]

Currently on hold, as the PR which added grouped nav was reverted in favor of the "8.x" approach, which is being tracked in #56232

[alexfrancoeur]

Recent design work to support this: #72659