Decouple yaml file and KubernetesClientConfiguration object

[tg123]

KubernetesClientConfiguration now can be created without yaml config
first step to address #24

Introduce go client style config creating functions

• Anonymous

var client = new Kubernetes(new KubernetesClientConfiguration
{
       Host = "http://127.0.0.1:8001"
});

• InClusterConfig

var k8sClientConfig = KubernetesClientConfiguration.InClusterConfig();
var client = new Kubernetes(k8sClientConfig);

• BuildConfigFromFlags like

//  BuildConfigFromConfigFile(string masterUrl = null, string kubeconfigPath = null)
var k8sClientConfig = KubernetesClientConfiguration.BuildConfigFromConfigFile();
var client = new Kubernetes(k8sClientConfig);

[krabhishek8260]

LGTM. Thanks for the PR.

[brendandburns]

combine the else and if into an else if

[brendandburns]

oh, wait, nevermind, I see there's a statement under the if...

[brendandburns]

extract "/var/run/secrets/kubernetes.io/serviceaccount/" and other strings out as constants?

[tg123]

another small question
Is this still not supported by windows after 1709?

[brendandburns]

Needs a rebase, but then LGTM.