This is the result of "make update" minus the testdata update which
will be committed separately.
Kubernetes-commit: 52b758c9b634fa56ab923c31dbf9e312b1a0c171
1. Add API definitions;
2. Add feature gate and drops the field when feature gate is not on;
3. Set default values for the field;
4. Add API Validation
5. add kube-proxy iptables and ipvs implementations
6. add tests
Kubernetes-commit: 7ed2f1d94d694c6c4fdb4629638c38b1cbda7288
