For for #209: createNotifications() is a server-side function now

See #209 . I've made `createNotifications()` a server-side method, which can be called from server versions of `comment` and `inviteUser` only. Therefore, noone can send a notification to user on behalf of Telescope without actually doing some action.

No latency compensation was available for `createNotifications`, so there was nothing to change in it.