Feat/allow k8s auth for all providers in examples

[snebel29]

Hi,
When running the examples you will get No Auth Provider found errors if your kubeconfig uses providers such as gcp or azure to name two.

$ make controller-example-onefile
go run ./examples/onefile-echo-pod-controller/main.go --development
2019/04/08 11:51:39 [ERROR] error creating kubernetes client: No Auth Provider found for name "gcp"
exit status 1
make: *** [controller-example-onefile] Error 1

The idea is to register all of the auth packages as well, and make examples to just work with a broader variety of authentication methods, out of the box.

$ make controller-example-onefile
go run ./examples/onefile-echo-pod-controller/main.go --development
go: finding github.com/Azure/go-autorest bca49d5b51a50dc5bb17bbf6204c711c6dbded06
2019/04/08 11:59:38 [WARN] no metrics recorder specified, disabling metrics
2019/04/08 11:59:38 [WARN] controller name not provided, it should have a name, fallback name to: *handler.HandlerFunc
2019/04/08 11:59:38 [INFO] starting controller
2019/04/08 11:59:40 [INFO] Pod added: kube-system/metadata-agent-5xcvk
...
...

I hope this change makes sense.

P.D: I had to force github.com/Azure/go-autorest to v10.14.0 as per explained here

Thanks

[slok]

Hi @snebel29!

Indeed it makes sense, thanks for contributing!