Additional input formats

[evansiroky]

This script should have the ability to accept different inputs in addition to the Cal-ITP agencies.yml file. The input options should be:

1. Ability to check a single URL as noted as a CLI argument option
2. An option for a CSV of URLs. The CSV format should simply have each URL on a newline. There should be a command line option to specify this kind of input and the location of the input file.
3. The Cal-ITP agencies.yml file. There should be a command line option to specify this kind of input and the location of the input file.