style: enable types_spaces rule

[kesselb]

I would prefer a unified way for union types ;)

Rule:

https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/blob/930dc93a1b90eb991d13e2766a340aa6922d4a2c/doc/rules/whitespace/types_spaces.rst

Examples:

catch(A | B) => catch(A|B)

function foo(): A | B => function foo(): A|B

Affected files in server:

   1) apps/files_versions/lib/Storage.php
   2) apps/theming/lib/Service/BackgroundService.php
   3) apps/dav/lib/BackgroundJob/OutOfOfficeEventDispatcherJob.php
   4) apps/dav/lib/BackgroundJob/UploadCleanup.php
   5) apps/dav/lib/CalDAV/WebcalCaching/RefreshWebcalService.php
   6) apps/dav/lib/CardDAV/UserAddressBooks.php
   7) apps/dav/lib/CardDAV/SystemAddressbook.php
   8) apps/settings/lib/Controller/UsersController.php
   9) apps/dav/lib/CalDAV/Schedule/IMipPlugin.php
  10) apps/files_sharing/lib/Controller/ShareAPIController.php
  11) lib/private/Avatar/AvatarManager.php