Implement open and select file in file manager [Linux]

Only few file managers are able to select files when started from the
command line.

xdg-mime is required to retrieve the default file manager. If it's not
available or the file manager is not able to automatically select files,
the containing directory will be opened as usual.
Merge pull request #2177 from pmzqla/open-select

Implement open and select file in file manager [Linux]