New specification

Adds new features:
- [x] Isolated validation (partial verif.) now supports multiple iterations
- [x] Secret recombination also supports multiple iterations
- [x] Alarms are raised when isolated validation passes but the whole hash doesnt
- [x] Bootstrap account creation is now possible.
- [x] Bootstrap accounts are updated to shielded accounts upon successful recombination

Terminology updates:
- [x] partial verification -> isolated validation
- [x] partial bytes -> isolated-check bits
- [x] lock/unlock -> bootstrapp
- [x] threshold account -> protector account
- [x] thresholdless account -> shielded account.