Refactor mainchain ledger functions to be DB driven

[gitsomedev]

• Each mainchain block ledger contains two different tables 1) table of account balances (maps: Address -> Balance) 2) table of completed polls / shards (maps: PollHash -> True)
• By using Level DB we can directly lookup values without loading into memory
• Each ledger can become VERY large, assume loading into memory will crash the PC
• Must have a function to copy a ledger for things like creating new blocks
• All mainchain ledger operations should occur through DB queries and interactions

MainchainLedgers\ JAHA9123AKSKAS_UTXO -> Account1: Balance -> Account2: Balance -> Account3: Balance JAHA9123AKSKAS_TXNS -> TxnHash1: True -> TxnHash2: True JAHA9123AKSKAS_SHARDS -> ShardHash1: True -> ShardHash2: True ...

[gitsomedev]

Completed