Remove GenesisParameters from wallet checkpoints

[Anviking]

Context

In ADP-356 we are integrating with Hard Fork Combinator.

In each wallet checkpoint we are currently storing:

checkpointGenesisHash       BlockId      sql=genesis_hash
checkpointGenesisStart      UTCTime      sql=genesis_start
checkpointFeePolicyUnused   Text         sql=fee_policy
checkpointSlotLength        Word64       sql=slot_length
checkpointEpochLength       Word32       sql=epoch_length
checkpointTxMaxSizeUnused   Word16       sql=tx_max_size
checkpointEpochStability    Word32       sql=epoch_stability
checkpointActiveSlotCoeff   Double       sql=active_slot_coeff

Note that

• epochLength, slotLength may change in the byron-to-shelley transition, but I don't think wallet checkpoints are suitable for keeping track of this.
• epochStability (i.e. k/ securityParam) is completely static
• We store recent TxParameters in a separate table
• We verify the genesisHash of the stored genesis checkpoint (seems useful)

Decision

I think we should remove everything but genesisHash.

Acceptance Criteria

• Redundant and potentially confusing information should be removed from wallet checkpoints

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Development

#1983

QA

[Anviking]

Maybe we should abort this for now because of https://input-output-rnd.slack.com/archives/GBT05825V/p1596197796271100?thread_ts=1596197783.271000&cid=GBT05825V

[rvl]

Yes when we have a better db migration system we can revisit this.