[ui] Policy Editor in the UI

[philrenaud]

Currently being tracked in draft #13976

---

• Acceptance tests
• Review design with Design team
• Change from "Operations" to something else (or keep it?)
• HCL syntax highlighting in CodeMirror
• handle autofocus
• clean up awkward spacing on "Are you sure?" prompt on Policy deletion
• add note and link to linked namespace/job/task/group (etc) to the Policy Show page
• if possible/easy, add a link from a job/task/group to a linked policy
• toast notifications for updates, deletes, and errors
• (maybe) expand or consolidate policy ability (can list etc. all currently depend only on a management token)
• review existing decisions on abilities and ability functionality (ie redirects)
• clean up the policy that is added automatically on "new". Move "Possible Policies" inline, and link out to "Possible Namespace Capabilities" instead of listing.