@charlesBochet told me we were moving to applying unicity contraints to all objects, including soft-deleted objects.

That might be annoying, so I think that in that case, we should automatically empty the trash (default value = 14 days). Salesforce does it every 15 days.

We should let the workspace owner change this default value (0 to xxx value, no reason to set a limit)
Even though it doesn't git well, I think we should hide it this in "Security" for now.

cc @Bonapara