what are the ENV variables

SERVER_GRPC_CONN_STRING: "grpc.NETMAKER_BASE_DOMAIN:443"

and

SERVER_API_CONN_STRING: "api.NETMAKER_BASE_DOMAIN:443"

used for if ports 8081 and 50051 still need to be opened? front end reverse proxy (nginx/caddy/traefik) connects those urls to those ports on port 443