Etna.1 - P-Chain Mempool
This version is backwards compatible to [v1.12.0](https://github.com/ava-labs/avalanchego/releases/tag/v1.12.0). It is optional, but encouraged. The plugin version is unchanged at `38` and is compatible with version `v1.12.0`. ## Configs - Added PebbleDB option `sync` which defau…