ethapi: reduce some of the wasted effort in GetTransactionReceipt

[omerfirmak]

Towards https://github.com/ethereum/go-ethereum/issues/26974

Best reviewed commit by commit.

From my benchmarks, it seems that the dominant cost is still the DB reads. Sender derivation seems to be negligible. Currently for a single receipt to be served we need to do multiple DB reads. If we are so concerned about the performance of this RPC, we should make the receipts self-contained so they don't need data from multiple queries to be stitched together to make a full receipt. This comes at the expense of slight increase in storage requirements but it might be acceptable given that EIP-4444 is in the works.