feature request: allow stashes creation

[rosenfeld]

It's currently possible to delete stashes directly from the UI while creating them is only possible through the API proxy (which is already great by the way). It would be interesting if the Dashboard could create and modify a stash directly from the UI.

Here's a use case. Our application stores any AJAX error to a mongo application. We want an alert to be created when that happens. But once we acknowledge the error, we'd like to store the last aknowledged error to fix the check until next AJAX error happens. One way of doing that is to add some "acknownledgedBy" attribute to the last entry in mongodb and checking for that. But another way of handling this directly from the dashboard would be to create a stash with the acknowledge time and person and use it in the checker. After created we would then update it after being notified by a new incident.