feat: use md5 auth by default

CHANGELOG.md

sbroad

src/access_control.rs

src/bootstrap_entries.rs

src/cli/args.rs

src/cli/expel.rs

src/schema.rs

test/conftest.py

test/int/test_access_control.py

test/int/test_acl.py

test/int/test_audit.py

test/int/test_basics.py

test/int/test_cli_connect.py

test/int/test_ddl.py

test/int/test_gostech_audit.py

test/int/test_sql.py

test/pgproto/auth_test.py

test/pgproto/types_test.py