Add "instant" Trino type

Some storage systems Trino connects to have a way store a point in time (instant), without time zone. In Java, this would correspond to java.time.Instant.

Examples:

• PostgreSQL's TIMESTAMP WITH TIME ZONE
• Cassandra's TIMESTAMP
• Teradata's TIMESTAMP
• Iceberg's timestamptz

Benefits

• Today, we should map these to TIMESTAMP WITH TIME ZONE in Trino (because it can store a point in time), filling the zone with UTC. If we implement "instant" type in Trino, we could map these to Trino without pretending zone was stored.

• Also, mapping to "instant" would help with INSERTs -- clearly indicating that there is no way to store a zone in the underlying storage.

• planning queries. TIMESTAMP WITH TIME ZONE zone-related behavior prevents predicates simplification/pushdown.

  • e.g. this is currently addressed for Iceberg by doing optimizations on the connector side
  • this can be solved alternatively by letting the connectors declare zone which all the TIMESTAMP WITH TIME ZONE values are in