Add Admin command to combine multiple cases

[C1701D]

Adding a command that combines multiple cases on the board into a single one can be useful for example for instances where a Client bounces and rejoins by creating a new case or for delayed cases.
This command should be Admin only (same as the remcase command) and needs to copy over relevant information (Dispatchers, Responders, Notes, Welcomed Status) but should probably not overwrite things like System, Hull Percentage etc. It might be best to save these details by having the command add the listcase output as a note.