Align field doc comments in the v1beta2 API package with the lowercase JSON name convention #2061

Part of #2017

What would you like to be added?

The api/v1beta2 types were copied from api/v1beta1, so most struct field doc comments still start with the capitalized Go field name, for example // Host is the hostname on which the API server is serving.

The Cluster API v1beta2 convention is for a field comment to start with the lowercase JSON field name, for example // host is the hostname on which the API server is serving. This matters because the field comment becomes the field description in the generated CRD.

This issue tracks aligning every field comment across the api/v1beta2 package to start with its lowercase JSON name.

It is kept as a separate cleanup because it touches almost every field in the package and would make the per-resource migration PRs noisy.