Move start of the maintenance mode to the ajax call

Make sure the update page is shown in a browser. And not an ajax request
Connect watcher failure function to the failure signal
Also check for needed upgrade in the Sabre Maintenance connector
Fix inexisting trashbin's sub-folders
duplicate verification
Dots in a filenames fix
Fixed problems with a dots in a filenames
Turn off theme before update
Add undefined verision variables
Merge branch 'master' into move-maint-start
Enable https authentication
Enable https authentication

Allow authentication using https:// as well as http://
Remove http:// from label and add placeholder
Update settings.php
Clear opcode caches after writing to the config file, fixes #3372
fix for autoloader while user logged in and system is in maintenance
use legacyDecrypt to decrypt key file like the previous files_encryption
fix re-encrypt legacy files
fix legacy key in until test
normalize path to prevent following split to fail