Add support for Sig Op calculation and adjusted sizes

[softsimon]

What we have to do now in the NodeJS backend should have native support in electrs.

We currently only support sigop calculation and adjusted vsize/weight on mempool-transactions, but on mined transactions we lose this. When implemented in Electrs we would be able to see the adjusted vsizes and sigop data in the frontend for mined transactions. This will also affect the CPFP clusters.

Reference:
https://github.com/mempool/mempool/blob/master/backend/src/api/transaction-utils.ts#L147