[epic] Add registry+v1 bundle validation

[perdasilva]

The rukpak/convert package currently assumes that it is always given a correct registry+v1 bundle to operate over. Until now, this has been ok since our use-cases presume that bundles have been validated by catalog curators, and our supported feature set has been relatively narrow (no webhook support, no api-service support, etc.).

Adding webhook support will require us to extract more information from different locations in the CSV, which also often reference other parts of the CSV, or bundle. Being able to assume things like referential integrity, non-duplication of data, etc. will make the webhook support simpler. For instance, conversion webhooks reference CRDs. If we can safely assume that the bundle has been appropriately validated, we don't need to check that the referenced CRD is in the bundle and that the CSV declares it as owned by the bundle.

Therefore, we should add a bundle validation layer with the appropriate checks to give us stronger guarantees of the validity of the bundle. This will be advantageous beyond the conversion/rendering code, i.e.:

• direct bundle installation
• avoiding erroneous data from being stamped out on the cluster