Full binary receive/send support

[workingjubilee]

See pksunkara/pgx_ulid#27 and this time the design should probably not have to pick between multiple traits like JsonInOutFuncs, PgVarlenaInOutFuncs, and InOutFuncs: there should be one way to serialize/deserialize it.

• https://www.postgresql.org/docs/16/sql-createtype.html
• https://www.postgresql.org/docs/current/catalog-pg-type.html

[workingjubilee]

Also see:

• feat: Support binary representation (SEND/RECEIVE for Vector type) tensorchord/pgvecto.rs#100
• External binary representation support (SEND/RECEIVE for custom types) #887
• Customizable serialization of PostgresType #965

[LucaCappelletti94]

This issue should likely be closed as PR #2068 has been merged.