Feature/shar 285 OIDC pkce

[MikeNeilson]

TODO:

• Processing of extensions to enable use of kc_idp_hint for CWBI keycloak derived from OpenAPI specification (possible that should be handled upstream and passed in.) - will handle in follow up PR, this is already large)
• Changes for any feedback.
• Attempted usage with hec-client-server Login Dialog Scaffold to verify implementation details and behavior.
• Remove System.out.println statement, or change to logger.

While a little drastic to remove the "Discovery Provider", to be honest I forgot about it when I started the work and by the time I found it again all of the same work likely would've been required and I don't see a way that easily integrates into the login dialog.

[MikeNeilson]

Also need to improve exactly how the wellknown is processed, currently two requests to that endpoint are made when it should really just be one. Was keeping it simple while I got the initial setup to work.

I also expect the new test to fail in the action as the browser won't be available and thus it should get stuck. need to determine exactly how to deal with that.

[MikeNeilson]

Seeing that it failed (got stuck) in the location I expected, I'm now implementing a Consumer to handle any auth callback. It will default to do nothing so it's easy to inject in the existing code.

[MikeNeilson]

This is ready for additional review. Changes to handle extensions, like the kc_idp_hint query parameter will be done in follow up PRs

[MikeNeilson]

Will take me a bit to implement all of that. thanks for the review.