* dep: upgrade secp256k1 to use btcec/v2 v2.3.2 and update insecurity pkg
* build ci: upgrade go to 1.19 and golangci-lint to 1.50.1
* docs: fix format that does not follow the goimports
* dep: redirect github.com/bnb-chain/tendermint to v0.31.13
* ci: disable GOPROXY
This commit adds pluggable consensus engines to go-ethereum. In short, it
introduces a generic consensus interface, and refactors the entire codebase to
use this interface.
