Copy a file from a shared folder to your home directory or another shared folder

[Tbaut]

When browsing a shared folder, we should have the ability to copy a file in our home directory, or any other shared folder.
I believe this should be a "share" menu entry similar to the one we currently have in the home directory.

Users could be able to select either another shared folder, or the home.

Open questions:

• should we allow to create a new shared folder at this stage, effectively re-using the modal we currently have
• calling the menu entry "share" is not immediately obvious that this would allow to copy to the home directory

What do you think?

[Tbaut]

I'll start with 1) and we can discuss further in the PR