pgproto integration

• Sibling issue for https://git.picodata.io/picodata/picodata/pgproto/-/issues/16
• See also: https://tomcam.github.io/postgres/

picodata run --pg-listen localhost:5432 
picodata admin ./admin.sql

CREATE USER "alex" WITH PASSWORD 'topsecret';
GRANT CREATE TABLE TO "alex";

psql postgres://alex:topsecret@localhost:5432

CREATE TABLE ...
INSERT ...
SELECT ...