Revert "Revert "Merge branch 'master' of https://github.com/discourse/discourse""

This reverts commit 20780a1eeed56b321daf18ee6bbfe681a51d1bf4.

* SECURITY: re-adds accidentally reverted commit:
  03d26cd6: ensure embed_url contains valid http(s) uri
* when the merge commit e62a85cf was reverted, git chose the 2660c2e2 parent to land on
  instead of the 03d26cd6 parent (which contains security fixes)

app/assets/javascripts/admin/models/admin-user.js

@@ -77,12 +77,6 @@ const AdminUser = User.extend({
     });
   },
 
-  revokeApiKey() {
-    return ajax(`/admin/users/${this.id}/revoke_api_key`, {
-      type: "DELETE"
-    }).then(() => this.set("api_key", null));
-  },
-
   deleteAllPosts() {
     let deletedPosts = 0;
     const user = this;