(core) Show usage banners in doc menu of free team sites

Summary:
Also fixes a minor CSS regression in UserManager where the
link to add a team member wasn't shown on a separate row.

Test Plan: Browser tests.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D3444

app/server/lib/HostedMetadataManager.ts

@@ -17,10 +17,10 @@ export class HostedMetadataManager {
   private _lastPushTime: number = 0.0;
 
   // Callback for next opportunity to push changes.
-  private _timeout: any = null;
+  private _timeout: NodeJS.Timeout|null = null;
 
   // Maintains the update Promise to wait on it if the class is closing.
-  private _push: Promise<any>|null;
+  private _push: Promise<void>|null;
 
   // The default delay in milliseconds between metadata pushes to the database.
   private readonly _minPushDelayMs: number;