refactor: simplify mempool to sorted queue and fix tx removal semantics#60

Zahnentferner merged 3 commits intoStabilityNexus:mainStabilityNexus/MiniChain:mainfrom

SIDDHANTCOOKIE:complex-architecture-cleanupSIDDHANTCOOKIE/MiniChain:complex-architecture-cleanupCopy head branch name to clipboard