Feat: protobuffer for ca-consensus heartbeat message

go.mod

packages/ca/heartbeat/proto/heartbeat.pb.go

packages/ca/heartbeat/proto/heartbeat.proto

packages/ca/heartbeat/proto/opinion_statement.pb.go

packages/ca/heartbeat/proto/opinion_statement.proto

packages/ca/heartbeat/proto/toggle_type.pb.go

packages/ca/heartbeat/proto/toggle_type.proto

packages/ca/heartbeat/proto/toggled_transaction.pb.go

packages/ca/heartbeat/proto/toggled_transaction.proto

packages/ca/heartbeat/serialization_test.go