Allow for certification of lightweight APIs

[dgmyrek]

There is a business need to support certification of APIs that may not include a set of specific DD fields - for example a lightweight API that includes a small subset of fields; none of which are Integer or Decimal. With that in mind we need the capability to skip tests on such fields without failing certification.

Another important consideration here is that ModificationTimestamp is not always going to be filterable, primarily to enforce replication restrictions in favor of live calls.

From Josh Darnell:

The Commander used to ignore any test that had an empty request URL in it, but as I've been moving in the direction of loading a fixed set of reference queries that can't be skipped, might no longer be a good option and I'd removed that code anyway. Perhaps a better solution would be to only test on known requirement IDs that are in the config, and if they're not present, skip the tests that rely on them. In other words, given requirementID is present in the RESOScript, run test.

This sounds like a great path forward to me.