* Remove unused PohServiceConfig::Step
* Clarify variable name
* Poh::hash() now takes an iteration counter
* man -> max
* Inline functions with single call site
* Move PohServiceConfig into GenesisBlock
* Add plumbing to enable real PoH on testnets
* Batch hashes to improve PoH hash rate
* Ensure a constant hashes_per_tick
* Remove PohEntry mixin field
* Poh/PohEntry no longer maintains tick_height
* Ensure a constant hashes_per_tick
* ci/localnet-sanity.sh: Use real PoH
* Rework Poh/PohService to keep PohRecorder unlocked as much as possible while hashing
Anything that affects how the ledger is interpreted needs to be
in the genesis block or someplace on the ledger before later
parts of the ledger are interpreted. We currently don't have an
on-chain program for cluster parameters, so that leaves only
the genesis block option.