feat: Move gtfsvalidator.cli package into new cli sub-module.

[bdferris-v2]

Summary:

Per discussion in #1188, I'm proposing to move the gtfsvalidator.cli package and associated classes for the GTFS Validator command-line interface into their own Gradle sub-module. This will support future modularization and packaging of the validator in ways that don't assume a CLI.

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[maximearmstrong]

LGTM! Thanks a lot @bdferris-v2

[maximearmstrong]

LGTM! Thanks a lot @bdferris-v2

[maximearmstrong]

I just tested the behavior locally, and it seems that the JAR file works, but there is a problem with the validators, even though all the status checks passed.

This is stdout when using the JAR file built on the master branch:

and now the stdout with the new JAR file:

Also, comparing the reports indicates a problem. Using master:

using the new one:

One problem I see here is that our acceptance tests don't detect this kind of problem. They verify that new rules don't add too many new errors, not if errors are disappearing. Perhaps we should change them to check other anomalies. I initially approved this PR because all tests were passing, so we should definitely find a way to capture problems like these. cc @isabelle-dr

[bdferris-v2]

@maximearmstrong indeed that's a subtle bug. When shadowJar minimization moved from main to cli, it caused the dynamically-loaded validators in main to be dropped since shadowJar is minimizing dependencies (which main now is). I added an exclude to fix this.

Regarding acceptance tests, maybe we can add an issue to track fixing that as well?

[maximearmstrong]

All good. I tested it locally and it worked well. Thanks for this modification @bdferris-v2

Regarding acceptance tests, I've opened #1232. I think we could add a few new rules. Your thoughts are welcome :)