Files - deal with dangling symbolic links

[bpasero]

So far we have ignored dangling symbolic links (with error) but we should still show them in places like the explorer and e.g. allow to delete them.

[bpasero]

Verification: create symbolic links (either file or folder) and delete the target. Make sure the links still show up in the file explorer with their link decoration on the right hand side. You can delete them, or open them and type to create them.