cmd/k8s-operator: ensure CRDs are always generated

This commit modifies the "generate" tool we use on the kubernetes operator
that produces helm chart and static manifest assets for CRDs.

Previously, this required always remembering to add new constants to
a `main.go` and did not have any mechanism to fail in CI if you forgot
to. Now this tool will iterate over all the CRDs and ensures that they're
in the places they're expected to be, with a test that will fail if they
are not.

This removes the requirement for remembering to add these constants
every time you have a new CRD.

Closes: #20594
Signed-off-by: David Bond <davidsbond93@gmail.com>
Signed-off-by: chaosinthecrd <tom@tmlabs.co.uk>