Feature/dt 462 add stop times validator

[josh-willis-arcadis]

Checklist

• Appropriate branch selected (all PRs must first be merged to dev before they can be merged to master)
• Any modified or new methods or classes have helpful JavaDoc and code is thoroughly commented
• The description lists all applicable issues this PR seeks to resolve
• The description lists any configuration setting(s) that differ from the default settings
• All tests and CI builds passing
• The description lists all relevant PRs included in this release (remove this if not merging to master)
• Code coverage does not significantly worsen (ideally it improves) (remove this if not merging to master)

Description

Adds an error check for duplicate arrival_times in stop_times.txt for a trip.

[josh-willis-arcadis]

First attempt at solving the issues. Need to address tests

[binh-dam-ibigroup]

Is there an error in src/test/resources/real-world-gtfs-feeds/VTA-gtfs-multiple-trips/stop_times.txt, and can you address the failing tests?

[binh-dam-ibigroup]

Looks good. We should leave this open in case MTC has feedback to give until they approve.

[josh-willis-arcadis]

This PR is no longer relevant and this logic can be found here: #11