CIP-159 - Account Address Enhancement - Phase 1

[lehins]

This is an umbrella ticket for the phase 1 implementation of promotion of reward accounts to proper accounts. Phase 1 meaning that for now we only implement ability to handle ADA, while addition of multi-assets to accounts will come in phase 2, which will likely come in Euler era.

List of tickets that need to be taken care of for the phase 1 of CIP-159 to be called complete:

• Add a directDeposits field to TxBody #5502
• Add accountBalanceIntervals field to TxBody #5503
• Rename RewardAccount to Account #5514
• Monoid instance for Withdrawals and DirectDeposits #5525
• ...