Use resource descriptor GVK for NewSession

[RedbackThomson]

Description of changes:
Some version of K8s do not reliably return TypeMeta information when you call apiReader.Get() (see kubernetes/kubernetes#3030 and kubernetes/kubernetes#80609). This is a known bug in controller-runtime that they don't plan on fixing.

Parts of the code, namely around setting up the user agent, currently rely on these fields - and they are currently being given an empty struct (with empty strings for all values). To work around this bug, this PR has introduced a new GroupVersionKind() getter in the ResourceDescriptor (replacing the existing GroupKind), which returns a static description of the GVK. Then, rather than referencing the RuntimeObject TypeMeta properties, we can reference this new GVK getter anywhere in the runtime. It also replaces any existing use of GroupKind to now use GroupVersionKind.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jaypipes]

This is obviously a breaking change so we will need to bump the minor version of the runtime and then code-generator. But I support the change after reading the various supporting GH issues for context.

[a-hilaly]

Neat 👍
Small breaking change but impact is huge.
/lgtm

[ack-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: A-Hilaly, jaypipes, RedbackThomson

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