Gtfs time zone handling

[lauriemerrell]

Description

This PR adds timezone localization information to GTFS schedule data:

• Adds feed_timezone in all schedule dimension tables (suppressed from open data publishing)
• Adds trip_start_timezone and trip_end_timezone to int_gtfs_schedule__stop_times_grouped and fct_daily_scheduled_trips
• Adds trip-localized and Pacific Time trip start and end times as DATETIMEs in fct_daily_scheduled_trips
• Uses service_date as the date summary level for stops, shapes, and daily schedule service summary per discussion in Slack with @tiffanychu90 and @edasmalchi
• Some assorted cleanup: fixes some existing table documentation
• Fixes daylight savings handling: service_date should not be cast directly to a timestamp (i.e. midnight); it is explicitly defined as starting from noon minus 12 hours to handle daylight savings

Follow-ups:

• Full refresh needed for schedule data (to add the feed_timezone field) -- can do immediately after merge: poetry run dbt run --full-refresh -s dim_schedule_feeds+,config.materialized:incremental --exclude fct_daily_rt_feed_files fct_hourly_rt_feed_files fct_hourly_rt_feed_files_success
• Updates from activity_date to service_date change in organization service summary reports#245
• We initially anticipated a full refresh for RT data but the RT portion of this issue will be addressed in GTFS RT date, time, and trip labeling updates #2489 and the fix for Handle frequency based trips in the warehouse #2471 instead of here (full refresh of Adjust trip updates materializations #2458 blocked by this collection of work)
• Fix materialization? Cluster fct daily scheduled trips / make stop times grouped incremental?: Migrated to GTFS schedule performance improvements #2488
• Reports site updates needed due to column name change in organization service summary table: Migrated to Updates from activity_date to service_date change in organization service summary reports#245

Resolves #2348

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature
• Breaking change (fix or feature that would cause existing functionality to not work as expected) -- changes date columns but relevant downstream places have been updated
• Documentation
• agencies.yml

How has this been tested?

Have run & tested affected tables locally. Looked specifically at daylight savings day service to confirm new implementation works.

Screenshots (optional)

[lauriemerrell]

Waiting on feedback on which date value to use for fct daily scheduled stops/shapes, once I can implement that, this will be good to go, unless it seems worth it to do RT date changes as part of this. I am conflicted about how to handle the nexus of this, #2413, and #2471.

[atvaccaro]

comprehensive docs 📖

[atvaccaro]

ty ty