Upgrade SabreDAV to 1.8.10

.idea/codeStyleSettings.xml

3rdparty

apps/files/appinfo/remote.php

apps/files_encryption/tests/webdav.php

apps/files_external/lib/webdav.php

apps/files_sharing/lib/api.php

apps/files_sharing/lib/connector/publicauth.php

apps/files_sharing/publicwebdav.php

lib/private/connector/sabre/ServiceUnavailable.php

lib/private/connector/sabre/aborteduploaddetectionplugin.php

lib/private/connector/sabre/auth.php

lib/private/connector/sabre/directory.php

lib/private/connector/sabre/exception/entitytoolarge.php

lib/private/connector/sabre/exception/filelocked.php

...rivate/connector/sabre/exception/unsupportedmediatype.php

lib/private/connector/sabre/exceptionloggerplugin.php

lib/private/connector/sabre/file.php

lib/private/connector/sabre/filesplugin.php

lib/private/connector/sabre/locks.php

lib/private/connector/sabre/maintenanceplugin.php