Feature: Add support for WebDAV network drives

**Is your feature request related to a problem? Please describe.**
I would like to be able to add Cloud Drives with a builtin FTP/WebDAV/... client like the various mobile file managers have.

**Describe the solution you'd like**
The ability to add cloud drives like WebDAV through the client natively. That is, these cloud drives would not be exposed to the system. Files would have its own builtin cloud storage client which would allow copying files to/from local folders. Solid Explorer is an example of a file manager which does this on Android.

**Describe alternatives you've considered**
I mount my cloud drives now via FUSE. It's not very fast, so I usually open WinSCP. I think a native client would be faster.