v18.1.0rc1

Release notes:

Stability improvements

• fix: captive core crashes with all invariants enabled
• base64 commands: properly parse multi lines
• log when meta stream writes are slow. This helps diagnose when systems like Horizon are not keeping up with traffic.
• Performance updates.Switch to native uint128_t, as well as a couple pr1 and pr2.
• Remove unnecessary protocol version checks in tests
• Fuzz liquidity pools
• Add a new config to wait for merges to complete when catching up
• Windows: uint128 and bucket merge fix
• Delete TmpDirs in order before shutting down in the Fuzzer

New features

None

Breaking changes

• Remove some redundant metrics. See PR for actual list.