(stable) Make dashboard arrange actions (move, add, remove) work again after read locking from "chaos reduction"
This no longer works after the read locking change from T13054. To make this function again, just add an explicit save() after layout adjustment. This should be more nuanced eventually, but all arrange operations are nonfunctional in a corrupting way at HEAD of master/stable, so stop the bleeding first.
- Created new empty and template dashboards.
- Moved panels.
- Added new and existing panels.
- Removed panels.
Differential Revision: https://secure.phabricator.com/D19123