Support Postgres Interval Types

[gregg-maiven]

Describe your feature request

Connector-x should support pg interval types.

Since last discussed in #26 (2022), it looks there are now several crates possibilities for supporting Postgres interval.

I see these:

• https://crates.io/crates/pg_interval
• https://github.com/piperRyan/rust-postgres-interval
• https://docs.rs/sqlx/latest/sqlx/postgres/types/struct.PgInterval.html
• https://docs.rs/diesel/latest/diesel/pg/data_types/struct.PgInterval.html

I am not sure if any are adequate. I am not a Rust programmer, so cannot speak to their quality.

Current workaround:

• change queries to extract(epoch from ....)