[WIP] Micro Runtime (#947)

* Add Get() and GetOptions.

* Removed watcher. Outline of client. YAML templates

* Added default service and deployment templates and types

* Added API tests and cleaned up errors.

* Small refactoring. Template package is no more.

* Ripped out existing code in preparation to small rework

* Reshuffled the source code to make it organized better

* Create service and deployment in kubernetes runtime

* Major cleanup and refactoring of Kubernetes runtime

* Service now handles low level K8s API calls across both K8s deployment
an service API objects
* Runtime has a task queue that serves for queueing runtime action
requests
* General refactoring

* No need for Lock in k8s service

* Added kubernetes runtime env var to default deployment

* Enable running different versions of the same service

* Can't delete services through labels

* Proto cruft. Added runtime.CreateOptions implementation in proto

* Removed proxy service from default env variables

* Make service name mandatory param to Get method

* Get Delete changes from https://github.com/micro/go-micro/pull/945

* Replaced template files with global variables

* Validate service names before sending K8s API request

* Refactored Kubernetes API client. Fixed typos.

* Added client.Resource to make API resources more explicit in code

runtime/kubernetes/client/templates.go

@@ -0,0 +1,93 @@
+package client
+
+var templates = map[string]string{
+	"deployments": deploymentTmpl,
+	"services":    serviceTmpl,
+}
+
+var deploymentTmpl = `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: "{{ .Metadata.Name }}"
+  namespace: "{{ .Metadata.Namespace }}"
+  labels:
+    {{- with .Metadata.Labels }}
+    {{- range $key, $value := . }}
+    {{ $key }}: "{{ $value }}"
+    {{- end }}
+    {{- end }}
+spec:
+  replicas: {{ .Spec.Replicas }}
+  selector:
+    matchLabels:
+      {{- with .Spec.Selector.MatchLabels }}
+      {{- range $key, $value := . }}
+      {{ $key }}: "{{ $value }}"
+      {{- end }}
+      {{- end }}
+  template:
+    metadata:
+      labels:
+        {{- with .Spec.Template.Metadata.Labels }}
+        {{- range $key, $value := . }}
+        {{ $key }}: "{{ $value }}"
+        {{- end }}
+        {{- end }}
+    spec:
+      containers:
+      {{- with .Spec.Template.PodSpec.Containers }}
+      {{- range . }}
+        - name: {{ .Name }}
+          env:
+          {{- with .Env }}
+          {{- range . }}
+          - name: "{{ .Name }}"
+            value: "{{ .Value }}"
+          {{- end }}
+          {{- end }}
+          command:
+          {{- range .Command }}
+          - {{.}}
+          {{- end }}
+          image: {{ .Image }}
+          imagePullPolicy: Always
+          ports:
+          {{- with .Ports }}
+          {{- range . }}
+          - containerPort: {{ .ContainerPort }}
+            name: {{ .Name }}
+          {{- end}}
+          {{- end}}
+      {{- end }}
+      {{- end}}
+`
+
+var serviceTmpl = `
+apiVersion: v1
+kind: Service
+metadata:
+  name: "{{ .Metadata.Name }}"
+  namespace: "{{ .Metadata.Namespace }}"
+  labels:
+    {{- with .Metadata.Labels }}
+    {{- range $key, $value := . }}
+    {{ $key }}: "{{ $value }}"
+    {{- end }}
+    {{- end }}
+spec:
+  selector:
+    {{- with .Spec.Selector }}
+    {{- range $key, $value := . }}
+    {{ $key }}: "{{ $value }}"
+    {{- end }}
+    {{- end }}
+  ports:
+  {{- with .Spec.Ports }}
+  {{- range . }}
+  - name: "{{ .Name }}"
+    port: {{ .Port }}
+    protocol: {{ .Protocol }}
+  {{- end }}
+  {{- end }}
+`