Suricata

Add support for the PostgreSQL protocol. Not only will this add support for PostgreSQL but other databases that use the PostgreSQL wire format like CockroachDB, and I believe there are others.

The protocol is documented here: https://www.postgresql.org/docs/13/protocol.html

Initial basics should include support for:
- connection username and database
- queries

Thought should be given to what could be normalized in terms of detection keywords and logging with other database protocols, such as MySQL.