Allow using BGP Control Plane

[robertvolkmann]

How to categorize this PR?
/area networking
/kind api-change

What this PR does / why we need it:
The BGP Control Plane allows us to announce the PodCIDR and the LoadBalancer IPs over BGP in a bare-metal environment.

Special notes for your reviewer:
https://docs.cilium.io/en/stable/network/bgp-control-plane/

[gardener-robot]

@robertvolkmann Thank you for your contribution.

[gardener-prow]

Hi @robertvolkmann. Thanks for your PR.

I'm waiting for a gardener member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[gardener-robot-ci-2]

Thank you @robertvolkmann for your contribution. Before I can start building your PR, a member of the organization must set the required label(s) {'reviewed/ok-to-test'}. Once started, you can check the build status in the PR checks section below.

[axel7born]

/ok-to-test

[DockToFuture]

/retest

[axel7born]

/lgtm