Add MobilityData GTFS Validator to validation step

[miles-grant-ibigroup]

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

Description

This PR integrates the MobilityData GTFS Validator into datatools, and adds a MobilityData validation to the GTFS validation step. Validation results are saved to a unique temporary folder, then loaded and inserted into Mongo. Failures are handled via the existing validation failure infrastructure.

Room for Improvement

• I'd like to perhaps see the MobilityData validation happen in a second thread, possibly in parallel to the existing validation. However, I'm not sure how to do this in the cleanest way, and the new validation isn't that slow, especially compared to the existing one.

Important Notices

The MobilityData validator requires a much newer version of the Java spec. I've updated by JDK to 18, and language level to 11!

Tests are failing due to an unrelated shape file export issue

[br648]

@miles-grant-ibigroup for review: #513. We should discuss at some point next week.

[br648]

@miles-grant-ibigroup I'm going to defer my review until this #513 is tested and merged.

[miles-grant-ibigroup]

Thanks Rob! All changes have been addressed

[br648]

All good. Good luck presenting the new data!

[philip-cline]

Looking good to me, seems to work well.