Create share link directly from other apps

### Is your feature request related to a problem? Please describe.
Often I find myself in the situation where I want to share a larger file (image, video) in a chat or mail, so I
* locate the file,
* share it to nextcloud,
* select an upload location,
* open the nextcloud app and
* locate the uploaded file,
* create a share link and
* then paste that.

It would be great if that process could be streamlined.

### Describe the solution you'd like
In the "share to" dialog I would love a new additional item "Link via Nextcloud". When selected, this would automatically upload the file to a set location (maybe something like "/InstantUpload/Share to Link"), create a share link and copy it to the clipboard.

### Describe alternatives you've considered
The approach in #1942 (make it easier to create a share link from the "successful upload" notification) would already be very helpful, but I don't think it is a real solution for the problem.

Instead of copying the link to the clipboard, the feature could also show a list of possible apps to share the link to. This is what samsung's stock "share to link" does, for example (see screenshot below).

### Additional context
Interface for [Samsung Link Sharing](https://play.google.com/store/apps/details?id=com.samsung.android.app.simplesharing) ("Link-Freigabe", follow the link for english screenshots). The user touches the top item in the first screenshot ("Link-Freigabe" / "Share link") and is presented with apps that they can share the link to in the second screenshot.