Add disconnected installs linter to DSPO

[HumairAK]

RHODS-7936 introduces a linter to make disconnected installs less likely to fail for things like referencing images by tag. Add this linter to the DSPO project.

@VedantMahabaleshwarkar is a good contact for this.

[HumairAK]

This will probably need to be moved downstream since we don't want to use sha images upstream.

We also don't reference images directly in deployments or kustomization.yamls, we do them via configs, so maybe a better alternative that applies to both upstream/downstream would be to ensure image fields are always parameterized in manifest deployed via dspo.

[rimolive]

I found some blockers to implement this check:

• kube-linter only checks for .yaml and .yml extensions. All operators generate template files from the k8s objects, with the extension .yaml.tmpl. This is hard-coded, so there is no parameter you can use to pattern-match these files
• The latest-tag check is a simple check that only checks for specific tags that aren't allowed. Again, I did not find a way to configure the pattern match for the forbidden tags
• There is an implementation (still WIP) to check for sha image references, but not yet merged.

That said, it is not possible to have a good linter to check for the disconnected installs, thus it requires us for a plan B.

[rimolive]

Proposed PR: #167