Draft: Consensus state provider

Second part of issue: #94 New state providers specific to account metadata and current account balances

The corresponding merge request in hive: hive!879

Info:

1. The whole database_api plugin with dependesnces is linked into haf shared library .so
   The database_api drags chain database and serves as the base for querying the state
2. sharedmemory.bin is created for every haf application context in PG_DATA the user given directory.
3. Any haf application using the consensus state provider can replay it forward any number of blocks
4. Each block is read from haf block api as json haf database with pqxx library queries and then consumed by the hive evaluator apply_block method. There is also a non-transactional variation that discards transaction data in favor of just blocks + operations.
5. 5M of replay takes

• 3 hours in json version
• in pqxx version
  • in 1 block chunks
    • with reestablishing the connection every chunk: estimated 526min(1M) x 5 = 2630 min = 43 h = 0.0063 sec per block
    • with reusing the connection: 81 minutes () : 0.00097 sec per bloc
  • in 100k block chunks
    • normally with transactions: 10 minutes
    • in non-transactional version: 6½ minustes
• after implementing forks:
  • block after block: 0.0018 sec
  • in 100k block chunks: 17 minutes

6. No validation happens during the replay