Feature: Full outer join scheduled & observed trips

[lauriemerrell]

To accomplish #2524, we would probably need to do the join that @evansiroky describes between fct_daily_scheduled_trips and fct_observed_trips in the warehouse. This ticket is intended to capture that portion of the request, because I decided that it would be too much to include in #2489.

Such a table comparing fct_daily_scheduled_trips and fct_observed_trips would need to have a full list of all trips from both tables. There are some things we will need to figure out how to capture:

• For all scheduled trips: was there an RT feed for that schedule feed on that day? If so, was the trip present in the RT feed or not? (We want to distinguish between cases where there is no RT data for a trip because no RT feed exists vs. cases where an RT feed exists but the trip was missing from that RT feed.)
• Do the times of any RT trip data align reasonably with what we expect from schedule? What do we do if not?
• How do we handle cases where the route ID disagrees between schedule and RT?

[lauriemerrell]

Ideally we would add some test to try to validate scheduled time vs. observed time and warn if they seem really out of whack

[lauriemerrell]

I think this is still needed, though the work in #2489 made it a lot easier

[lauriemerrell]

Closing as a duplicate of #2524 which outlines specific need for this table