Add golden tests to all templates in abcxyz and run them in CI

Currently, we have good golden test coverage for templates inside the abc repo, but not as much for templates in other repos inside the abcxyz github org. Let's do:

1. Add golden tests: for each spec.yaml, there should be at least one test that covers it. If the spec.yaml does something complex with conditional control flow, we should consider adding multiple tests that cover all the cases.
2. Integrate the abc repo with those templates in other repos so we run them as part of our CI process. This might help avoid bugs like #428 in the future. We'd have a list of repos that we check out in a github action then run all their golden tests.