kubernetes: Traffic Policy and Topology Aware Routing should not be exclusive

What happened:

I believe the code is currently written in a way so that only one of the following will be implemented (in order):

• ExternalTrafficPolicy
• InternalTrafficPolicy
• Topology Hints

What you expected to happen:

Configurations like externalTrafficPolicy=Local + internalTrafficPolicy=Local should be valid. Similarly, it should be able to enable topology if only one of externalTrafficPolicy or internalTrafficPolicy are set to local.

(This originated from https://github.com/kubernetes/website/pull/27032#discussion_r595399116).

/sig network /cc @maplain @andrewsykim @thockin