kubernetes module: flannel support, minor fixes

- add flannel support
- remove deprecated authorizationRBACSuperAdmin option
- rename from deprecated poratalNet to serviceClusterIpRange
- add nodeIp option for kubelet
- kubelet, add br_netfilter to kernelModules
- enable firewall by default
- enable dns by default on node and on master
- disable iptables for docker by default on nodes
- dns, restart on failure
- update tests

and other minor changes