Added CSRF checks

apps/bookmarks/ajax/addBookmark.php

apps/bookmarks/ajax/delBookmark.php

apps/bookmarks/ajax/editBookmark.php

apps/calendar/ajax/calendar/delete.php

apps/calendar/ajax/calendar/edit.php

apps/calendar/ajax/calendar/new.php

apps/calendar/ajax/calendar/update.php

apps/calendar/ajax/event/delete.php

apps/calendar/ajax/event/edit.php

apps/calendar/ajax/event/move.php

apps/calendar/ajax/event/new.php

apps/calendar/ajax/import/import.php

apps/calendar/ajax/settings/setfirstday.php

apps/calendar/ajax/settings/settimeformat.php

apps/calendar/ajax/share/changepermission.php

apps/calendar/ajax/share/share.php

apps/calendar/ajax/share/unshare.php

apps/external/ajax/setsites.php

apps/files/ajax/delete.php

apps/files/ajax/move.php