Enhancement: Add tag support

Web now supports tags on resources to enhance the way of organizing and working. Tags are visible in the files list and can also be searched to quickly filter tagged files.

https://github.com/owncloud/web/pull/7388
https://github.com/owncloud/web/pull/7385
https://github.com/owncloud/web/pull/7442
https://github.com/owncloud/web/pull/7754
https://github.com/owncloud/web/pull/8067
https://github.com/owncloud/web/pull/8157
https://github.com/owncloud/web/pull/8309
https://github.com/owncloud/web/pull/8405
https://github.com/owncloud/web/pull/8502
https://github.com/owncloud/web/pull/8794
https://github.com/owncloud/web/issues/7134
https://github.com/owncloud/web/issues/8149
https://github.com/owncloud/web/issues/8220
https://github.com/owncloud/web/issues/8253
https://github.com/owncloud/web/issues/8254
https://github.com/owncloud/web/issues/8390
https://github.com/owncloud/web/issues/8645
