Rewrite command line arguments parsing

[deric]

Use less code to do the same thing. Arguments are defined in one place and can be read from ENV without using bash script to translate ARGS.

• Upgraded Ruby base image
• Fixed insecure CA algorithm
• Short options remained the same:

usage: /etc/k8s/kube_tool.rb [options]
    -o, --os                    The OS that Kubernetes will run on
    -v, --version               The Kubernetes version to install
    -r, --container_runtime     The container runtime to use. This can only be "docker" or "cri_containerd"
    -c, --cni_provider          The networking provider to use, flannel, weave, calico, calico-tigera or cilium are supported
    -p, --cni_provider_version  The networking provider version to use, calico and cilium will use this to reference the correct deployment download link
    -t, --etcd_ip               The IP address etcd will listen on
    -i, --etcd_initial_cluster  The list of servers in the etcd cluster
    -a, --api_address           The IP address (or fact) that kube api will listen on
    -b, --key_size              Specifies the number of bits in the key to create
    -d, --install_dashboard     Whether install the kube dashboard
    -h, --help                  print the help

After upgrading the golang base image #589, the cloudflare/cfssl doesn't have fixed version and might eventually break with any breaking change. Currently generating CA certificates is broken.