Add initial behavioral tests to verify patches and templates work as intended

[displague]

This PR also includes an example that I used to replicate the validation issue and confirm that my tests fixed it; I intended to remove it before merge, since it's really not an example of how the SDK should be used, but I'm open to keeping it. In the meantime, at least, this PR can be poked at by checking it out locally and running these commands in the project root

Can we preserve this as a test?

If https://github.com/equinix-labs/metal-java/tree/main/equinix-functional-test/src/test/java/com/equinix/test tests "functional" changes, perhaps a "behavioral" set of tests could be kept in the project to ensure that our patches and templates changes (work-arounds) behave as we expect.

Approving as-is. We can open a new issue to address this.

Originally posted by @displague in #163 (comment)