[WIP] Added OpenStack LoadBalancer classes support #1111
Co-authored-by: Uwe Krueger email@example.com
What this PR does / why we need it:
Special notes for your reviewer:
We will hopefully merge #1076 soon. It doesn't make sense to merge this one now because it would postpone #1076 and produce additional effort for the colleagues that are implementing the OpenStack extension controller.
Can you open a PR against the gardener-extensions repo and do these adaptions in the OpenStack controller?
Can you adapt this PR to only include the API changes that are required in the