Generate the cleanup service

[stefjoosten]

After the migration of system $A$ to $B$, the remainders of $A$ and the migration system have to be removed so that only $B$ remains. This involves deleting the right tables from the database. The Ampersand compiler has to provide the information for the cleanup service in the back-end (see issue AmpersandTarski/Prototype#112).

Task

Determine the difference set that enables the back-end to realize its ``cleanup service’’ and propagate it to the back-end.