Enhancement: Create shortcuts

We've added a new functionality to add to shortcuts to web, those can be created via the "+ New" context menu.
Users can enter URLs or pick a file via the drop down menu and create a '.url' file.

'.url' files can be opened via web or downloaded and opened on the desktop.

https://github.com/owncloud/web/pull/9890
https://github.com/owncloud/web/pull/9908
https://github.com/owncloud/web/pull/9936
https://github.com/owncloud/web/pull/9971
https://github.com/owncloud/web/issues/9796
https://github.com/owncloud/web/issues/9887
https://github.com/owncloud/web/issues/9850
https://github.com/owncloud/web/issues/9963
https://github.com/owncloud/web/issues/9969
