Remove restoring soft deleted entries part 2

There is no need to reuse deleted entries, because they will be archived after
db-archiving implementation. And restoring soft deleted entries produce some
problem with db-unique-keys implementation. So the best way is to remove it.

instance_type_access_add() method
Remove restoring soft deleted instance_type_access entries

Add missing tests for instance_type_access_add

blueprint db-session-cleanup

Change-Id: I82ee56b50a8422a4b620f4e58967258bac7c01c6
Merge "Remove restoring soft deleted entries part 2"