Examine use of time zone setting in database calls

In the agActor there are a number of database calls where SET TIME ZONE 'UTC'; is prepended to the actual query of interest, and then individual columns are converted to HST within the sql statement. A few things should change with this:

• The time zone should not be set on a per-call basis but instead set once at either a) the database role level, b) the database level or c) the connection level. I would imagine we want to set the entire database to UTC.
• The column level conversions should not be done in SQL but should be done in the caller code on the returned results. This is more work.
• The term HST should not be used, it should be Pacific/Honolulu. (IANA name).

Note that the use of the SET TIME ZONE call prepended to sql statements will have problems with pgBouncer and affects our implementation of INSTRM-2614.

I was only looking at the agActor, so other actors and code should also be checked.