configurable end/start of day about hey_3 HOT 1 OPEN

Just realized that a nice way to handle this is to

1. limit choice to an even hour. E.g. 4 AM not 4:44 AM
2. whenever doing calculations for reporting purposes just have them run within a time zone that corresponds to the requested hour.

That is to say, if i'm in Eastern Standard Time and I set my "end/start of day" to 4 am then behind the scenes, and only for the purposes of finding day/week/month boundaries, change my time zone from GMT -5 (EST) to GMT -9 (AKST). Midnight AKST is 4AM EST. Once we've done that we can leverage all of Raku's built in day/month functionality without doing any funky math & custom day boundary calculations everywhere.

a simple example: hey log 3 days

1. read in config for start/end of day
2. see that it's 4 hours off and add +4 to current time zone.
3. calculate the start of the day 3 days ago.
4. get that as an epoch time.
   (at this point we're done mucking with the fake time zone)
5. query the db for entries from that time forward
6. pass the results on for reporting
   user output works as it already does with the current time zone.

from hey_3.