Undelete: deleted files, calendar events, contacts and Sieve scripts are kept and restored where they were (UD-1, UD-8 to UD-11)

Files, events and contacts are noted when deleted for good and archived by
the unindex task when retention is on; Sieve scripts are archived at
deletion. A restore goes back to its folder, calendar or address book if it
still exists, takes a free " (restored)" name, comes back inactive for
scripts, and is refused over quota with the item left archived.
Acceptance tests 6, 8 and 12.

crates/groupware/src/lib.rs

@@ -16,6 +16,7 @@ pub mod cache;
 pub mod calendar;
 pub mod contact;
 pub mod file;
+pub mod inbuxa; // inbuxa: undelete notes
 pub mod scheduling;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]