Add button to copy internal link when sharing

[juliushaertl]

When sharing a table (or view) users might want to share the internal link to it in a chat or elsewhere. Currently it is not obvious that the URL is the same for every user.

We should add a copy button for the internal link in the sharing sidebar, similar to how it is done in files that just copies the current view or table URL to the clipboard.

Example entry from the files app:

Sharing tab where the entry should be added: