This replaces `ver_rct_non_semantics_simple_cached()` with an API that offloads
the responsibility of tracking input verification successes to the caller. The
main caller of this function in the codebase, `cryptonote::Blockchain()` instead
keeps track of the verification results for transaction in the mempool by
storing a "verification ID" in the mempool metadata table (with `txpool_tx_meta_t`).
This has several benefits, including:
* When the mempool is large (>8192 txs), we no longer experience cache misses and unnecessarily re-verify ring signatures. This greatly improves block propagation time for FCMP++ blocks under load
* For the same reason, reorg handling can be sped up by storing verification IDs of transactions popped from the chain
* Speeds up re-validating every mempool transaction on fork change (monerod revalidates the whole tx-pool on HFs #10142)
* Caches results for every single type of Monero transaction, not just latest RCT type
* Cache persists over a node restart
* Uses 512KiB less RAM (8192*2*32B)
* No additional storage or DB migration required since `txpool_tx_meta_t` already had padding allocated
* Moves more verification logic out of `cryptonote::Blockchain`
Furthermore, this opens the door to future multi-threaded block verification
speed-ups. Right now, transactions' input proof verification is limited to one
transaction at a time. However, one can imagine a scenario with verification IDs
where input proofs are optimistically multi-threaded in advance of block
processing. Then, even though ring member fetching and verification is
single-threaded inside of `cryptonote::Blockchain::check_tx_inputs()`, the
single thread can skip the CPU-intensive cryptographic code if the verification
ID allows it.
Also changes the default log category in `tx_verification_utils.cpp` from "blockchain" to "verify".
Reduce bloat in the python RPC Response class by making better use of
superclass methods and recursion. As part of this change, add tests for
the Response class.