polkadot builds (gitlab), releases (docker) and deployment (kubernetes) (#48)

* ci: add Dockerfile and its build

* make docker version tag

* polkadot with static ip address in nodeport stateful set on kubernetes

* use helm for templating

* enable rbac for polkadot

polkadot/scripts/kubernetes/templates/serviceaccount.yaml

@@ -0,0 +1,12 @@
+{{- if .Values.rbac.enable }}
+# service account for polkadot pods themselves
+# no permissions for the api are required
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  labels:
+    app: polkadot
+    chart: {{ .Chart.Name }}-{{ .Chart.Version }}
+    release: {{ .Release.Name }}
+  name: {{ .Values.rbac.name }}
+{{- end }}