* Update kubeadm-init.md
Fix broken kubeadm token link
* Fix more broken links in kubeadm-init.md
Broken links are fixed including kubeadm-join, kubeadm-upgrade, and kubeadm-reset
1) Remove missing links about kube-apiserver, kube-controller-manager
and kube-scheduler. Link to the high-availability page, which
isn't exactly a full replacement.
2) Add section about kube-proxy parameters.