(core) Adding import from google drive to the home screen

Summary: Importing from google drive from home screen (also for anonymous users)

Test Plan: Browser tests

Reviewers: dsagal, paulfitz

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2943

app/server/lib/DocPluginManager.ts

@@ -147,7 +147,7 @@ export class DocPluginManager {
   }
 
   /**
-   * Returns a promise which resolves with the list of plugins definitions.
+   * Returns a list of plugins definitions.
    */
   public getPlugins(): LocalPlugin[] {
     return this._localPlugins;