Overhaul for get-server v. 2.0.0

Since get-server downloads its own jarfile this commit overhauls a lot
of the minecraft deploy to match the new strategy. It also updates the
README and adds makefile targets for a few new commands.

helm/templates/deploy.yaml

@@ -23,13 +23,6 @@ spec:
         volumeMounts:
         - mountPath: /downloads
           name: data
-      - name: download-server
-        image: {{ .Values.get_server.image }}
-        imagePullPolicy: Always
-        command: ["bash", "-c", "curl -o server.jar $(cat SERVER_VERSION)"]
-        volumeMounts:
-        - mountPath: /downloads
-          name: data
       containers:
       - name: {{ .Release.Name }}
         image: {{ .Values.image }}