Merge pull request #19872 from owncloud/share2.0_sharemanager

apps/files_sharing/api/ocssharewrapper.php

apps/files_sharing/api/share20ocs.php

apps/files_sharing/appinfo/routes.php

apps/files_sharing/tests/api/share20ocstest.php

lib/private/share20/defaultshareprovider.php

lib/private/share20/exception/backenderror.php

lib/private/share20/exception/sharenotfound.php

lib/private/share20/ishare.php

lib/private/share20/ishareprovider.php

lib/private/share20/manager.php

lib/private/share20/share.php

tests/lib/share20/defaultshareprovidertest.php

tests/lib/share20/managertest.php