Implement the Tier-0 Mode

The Tier-0 needs are very special, and we don't have yet a fully
flexible and functional safe mode. This implements an specific
Tier-0 mode which is suitable for Tier-0 custodial, move subscriptions
although it has a few bits hardcoded.
Merge pull request #4634 from dballesteros7/morePhedex

Implement the Tier-0 Mode