When searching for files or using the Images view, allow going to the location of a file

### Is your feature request related to a problem? Please describe.
Since there's (on all of Nextcloud) no way to select which folders to use for Images/Photos/Gallery, only a way to exclude some folders (using a .nomedia file), I'd like to find _where_ are stored pictures showing in the gallery, so I can exclude the relevant folder. There's no way to do that both in the Properties of the file (which is accessible from), neither when searching for the file or having it in the Favorites view.

### Describe the solution you'd like
Except when browsing from the Files view, add a context menu entry to files to open their containing folder.

### Describe alternatives you've considered
Showing the ful' path, maybe behind a toggle, on the Properties view.

Please correct me if I'm wrong about anything.