Move document improvements (#927)

* Show all collections in UI

* Introduce command pattern

* Actually remove from previous collection

* Stash

* Fixes: Promises resolved outside of response lifecycle

* 💚

* 💚

* documentMover tests

* Transaction

* Perf. More in transactions

server/policies/document.js

@@ -14,7 +14,7 @@ allow(User, ['read', 'delete'], Document, (user, document) => {
   return user.teamId === document.teamId;
 });
 
-allow(User, ['update', 'share'], Document, (user, document) => {
+allow(User, ['update', 'move', 'share'], Document, (user, document) => {
   if (document.collection) {
     if (cannot(user, 'read', document.collection)) return false;
   }