Closes#14578
The Jira Cloud guide applies to all Jira deployments already, so we
don't need to maintain separate guides. This change renames the Jira
Cloud guide so it's about Jira in general.
Reorganize our Access Request guides
Fixes#13696
Most guides to Access Requests are currently not listed on the sidebar,
and the guides that are listed are available for Cloud as well as
Enterprise. This change makes it easier to find our Access Requests
guides by moving them to the Access Controls section and listing all
guides on the sidebar. It adds the "Access Requests" and "Access Request
Plugins" subsections to "Access Controls".
Since the Access Controls section includes one subsection, called
"Guides", this change also renames that subsection--and adds a
descriptive intro paragraph to the section's menu page--in order to
accommodate the Access Requests and Access Request Plugins subsections.
Move some guides into "Access Requests"
