Cache travel time results in the database

[Nate-Wessel]

Once results are calculated, it wouldn't take much extra time/effort to store them in the database, along with all the params that defined the request, such as we started doing here: https://github.com/Toronto-Big-Data-Innovation-Team/cycling_before_after/blob/main/motor_vehicle_travel_times/motor_vehicle_travel_times.sql

Any travel time request then could start with a quick lookup to see if we already know the answer... and end if necessary with an update to that table (possibly after returning results to keep things snappy?).

Would want to make the app backend aware of its version (commit hash) as well to ensure consistency in case the calculations change.

[Nate-Wessel]

@AdK0101 was working on a script in a similar vein here

[Nate-Wessel]

To make this really snappy, we might want to drop the links, etc from the travel time output. They're never really used there anyway, to my knowledge.