* llmq: Detach dash-q-cachepop from caller
There should be no reason to keep this tread attached
to its parent, if so, let me know.
* llmq: Avoid nullptr access for pindexStart in ScanQuorums
* llmq: Add cacheKey in ProcessCommitment
* llmq: Erase minable commitments if they have been processed
* llmq: Add CLLMQUtils::InitQuorumsCache
* llmq: Use unordered_lru_cache for quorumsCache and rename it
* llmq: Use unordered_lru_cache for hasMinedCommitmentCache and rename it
* llmq: Drop redundant check
* llmq: Rename nMaxCount2 -> nScanCommitments
* llmq: Refactor storeCache -> fCacheExists
* llmq: Rename maxCount -> nCountRequested
* llmq: Rename result -> vecResultQuorums
* llmq: Return an empty vector if the are zero elements requested
* unordered_lru_cache: Add max_size()
* llmq: Partially reuse existing cache if more than max is requested
* llmq: std::map<LLMQType, unordered_lru_cache<...>> for scanQuoumsCache
* llmq: Drop params
* llmq: Only emplace to cache if there is something available
