Update Postgres connector function to support the 'interval' data type

[Richard-SNN]

I have a Postgres query (really TimescaleDB) that returns multiple intervals as a datatype. Unfortuantly to get the data into Tulip I have to use the EXTRACT('epoch' from <...>) method to convert it to an integer.

This works, but then I will have to convert back to an interval data type in Tulip.

[Beth]

Thanks for the suggestions Richard! Will add it to our list