Console panel, collapsible panels, Add on the Members panel

- Server settings > Console sends a raw console command for staff with @css/rcon
  (POST /api/admin/rcon). It doesn't wait for the server; the output is only logged.
- Staff & ranks and Server settings panels fold up by clicking their heads. All but
  Ranks and Server start folded; a folded Ranks panel shows the selected rank.
- The Members panel has an Add button that opens Add staff with that rank picked.
- The public rank log shows a rank being given as Promoted and taken away as Demoted.

README.md

@@ -43,6 +43,7 @@ RCON. Without it the panel still works, but shows the server as offline and can'
   | See IP addresses | `@css/showip` |
   | Change map | `@css/changemap` |
   | Server cvars | `@css/cvar` |
+  | Raw console commands (Server settings > Console; sent without waiting, output only logged) | `@css/rcon` |
   | See the Staff & ranks page | `@zio/webpanel` |
   | Give and remove verification overrides | `@zio/verify` (not on themselves, unless Root) |
   | Ranks, staff, SimpleAdmin settings, reload admins, GroupVerify's group and on/off | `@css/root` |