Report incompatible InstaScale custom image in CR conditions

[astefanutti]

With #120, it's possible to specify a custom container image for the InstaScale controller.

While that mechanism is convenient, it's also very flexible, and can lead to undefined behaviors, e.g., when the specified image is not compatible with the version of the running CodeFlare operator, and the CRDs that are bundled with it.

Ideally, such incompatibilities, as well as unrelated images, should be detected, and reported into the InstaScale resource conditions.

One option may be to rely on image metadata, and a priori knowledge of the backward compatibility lineage.

[astefanutti]

/cc @anishasthana

[astefanutti]

This has become obsolete with #279.