Cardano Updates

Signed-off-by: William Hankins <[email protected]>

feat: extend spo state to store historical data; refactor accounts state

- Introduced  struct to encapsulate live stake data.
- Implemented  method in  to calculate live stake metrics.

refactor: rename & expand epoch activity counter module; introduce BlockHash type

- Introduced  and  structs to include transaction hash and certificate index.
- Enhanced  and  implementations to store historical updates and also handle governance procedures.
- Refactor spo_state to use consistent config constants.
- Make some subscriptions optional which will be enabled when stake_addresses are enabled.

Handles Shelley (until Allegra) bug where stake deregistrations
are still accounted up to the point the Haskell node starts the
reward calculation, rather than the epoch boundary.

Also makes our normal reward calculation rollback-proof, which
is a good thing anyway.

- improve pool's delegators calculation

- Remove aggregated_spo_state from spo_state and use epochs_history instead for active_stakes information

- Added utxo values map and sum query to accounts state

- Added optimial pool sizing query to accounts-state to calculate pool's saturation

- Remove redundant curly braced struct type in both accounts and pool queries

- Enhance serde for Pool's Rest response type to reduce duplicated serialization

Deposits now repaid after snapshot taken, to avoid them changing
the stake

This revealed another problem, which is if an SPO withdraws all
its stake after a snapshot but still produces blocks, it would
have previously been ignored.  The early repayment of the deposit
previous masked this.

Switched logging of epochs in rewards and snapshots to be the
epoch just left - that is, the one that blocks are being counted for

Signed-off-by: William Hankins <[email protected]>

Signed-off-by: William Hankins <[email protected]>

feat: optimize asset storage and add history / policy assets REST handlers