Refactor CAT pool to become nonce aware

[ninabarbakadze]

Description

Currently, transactions are prioritised based on the fee not taking nonce order into account. We can make the mempool nonce aware where transactions would be partially ordered by both nonce and priority, ensuring high-priority transactions are processed sooner while maintaining nonce order. This would allow users to:

• Cancel transactions
• Replace transactions with the same nonce and higher fee

Acceptance Criteria

• CAT pool is nonce aware

[rootulp]

CAT pool isn't the default yet and AFAIK we haven't recommended its use on mainnet. Have we considered adding this feature to the other mempools (especially the prioritized mempool)?

[ninabarbakadze]

IIRC @evan-forbes was talking about how CAT will be the only supported mempool soon. Shipping this feature will most likely align with shipping CAT

[rootulp]

Thanks for the context. If we aren't going to add this feature to the other mempools, IMO we should work on a few other issues before this one:

1. Recommend CAT mempool on testnets + mainnet
2. Deprecate other mempools (needs discussion)
3. Lastly, this issue