CLOUDSTACK-7590 Deletion of Account is not deleting the account from the database

Revert "CLOUDSTACK-7073: Added domainId field to the user table in order to restrict duplicated users creation on the db level"

This reverts commit 5a96d8ef5cbc88df366016ae9dd7ee46e4ca417a.

Conflicts:
	setup/db/db/schema-440to450.sql