Write script for updating/validating feed files

[rachelekm]

Refactor the "Getting the GTFS file" section of the deployment instructions so that any manual actions are automated, including:

1. Editing SEPTA bus routes.txt files to convert trolleybuses
2. Confirm no error messages in feed corresponding .html file
   • If newline error, edit corresponding file
   • Else, continue to feedvalidator script
3. Updating the feedvalidator script
   • This used to work and could validate each file, confirming if issues with GTFS spec. May be outdated.
   • If invalid, stop build for manual fix

Bring these scripts into the new GA workflow