Add initial provider conformance tests

[negz]

Description of your changes

Fixes some but not all of https://github.com/crossplane/conformance/issues/10

We ensure the provider is installed successfully, and delivers only conformant CRDs. Thanks to kextv1.JSONSchemaProps I now have 7 PhDs in cmp.Option.

I have:

• [x] Read and followed conformance's contribution process.
• [x] Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

I've tested that crossplane/provider-gcp is compliant.