Each validator will generate a random cookie on startup that it will
include in each of its validations. This will allow validators to detect
when more than one validator is accidentally operating with the same
validation keys.
These changes use the hash of the consensus transaction set when
characterizing the mismatch between a locally built ledger and fully
validated network ledger. This allows detection of non-determinism in
transaction process, in which consensus succeeded, but a node somehow
generated a different subsequent ledger.
These changes augment the Validations class with a LedgerTrie to better
track the history of support for validated ledgers. This improves the
selection of the preferred working ledger for consensus. The Validations
class now tracks both full and partial validations. Partial validations
are only used to determine the working ledger; full validations are
required for any quorum related function. Validators are also now
explicitly restricted to sending validations with increasing ledger
sequence number.
