Migrate from urfave/cli to cobra (#426)

* wip

* env var fix

* cluster create

* cluster create and delete

* cluster list

* cluster cmd

* kubeconfig

* policy create

* policy delete and list, and added root commands

* removed urfavecli from k3kcli

* fix policy command

* k3k-kubelet to cobra

* updated docs

* updated go.mod

* updated test

* added deletion

* added cleanup and flake attempts

* wip bind env

* simplified config

docs/cli/k3kcli.md

@@ -0,0 +1,18 @@
+## k3kcli
+
+CLI for K3K
+
+### Options
+
+```
+      --debug               Turn on debug logs
+  -h, --help                help for k3kcli
+      --kubeconfig string   kubeconfig path ($HOME/.kube/config or $KUBECONFIG if set)
+```
+
+### SEE ALSO
+
+* [k3kcli cluster](k3kcli_cluster.md)	 - cluster command
+* [k3kcli kubeconfig](k3kcli_kubeconfig.md)	 - Manage kubeconfig for clusters
+* [k3kcli policy](k3kcli_policy.md)	 - policy command
+