Refresh if maintenance mode is over

Using status.php for this.
I modified status.php to also show, whether we're in maintenance.

Checks every 20 seconds if maintenance is over, if yes: reload.
Add custom hex2bin implementation for 5.3

Fixes https://github.com/owncloud/core/issues/11004
Add X-UA-Compatible to all templates

Replaces https://github.com/owncloud/core/pull/10850
Merge pull request #3937 from owncloud/refresh_if_maintenance_is_over

Refresh if maintenance mode is over
Merge pull request #11007 from owncloud/replaces-10850

Add X-UA-Compatible to all templates
fix notification visibility, fix #11016
Merge pull request #11006 from owncloud/addCustomHex2BinImplementationBecauseSupporting53IsSomethingReallyReallyCoolAndWeAreObviouslySomeOfTheCoolGuys

Add custom hex2bin implementation for 5.3
Merge pull request #11018 from owncloud/fix-notification-layer

fix notification visibility, fix #11016
Add timeout to user and group deletion notification

Added timeout in DeleteHandler to auto-delete after a delay.

Fixed issue where OC.Notification.hide() was called twice in a row when
deleting multiple entries, causing the second notification to disappear.
Fixed issue where "undo" click event handler was registered multiple
times when calling setNotifications() twice.
Added JS unit tests for the DeleteHandler class.