Add dev/stg/prod environments with per-env values, configmaps and secrets

- Move env-specific config into environments/<env>/{values,configmap,secret}.yaml
  for both nginx-chart and mysql-chart (dev, stg, prod)
- Make templates env-agnostic: resource names come from values
  (configMap.name, secret.name)
- nginx deployment mounts env ConfigMap and loads env Secret via envFrom
- mysql statefulset reads DB config from ConfigMap, passwords from Secret
- Remove mysql-chart/templates/secret.yaml (secrets are now per-env manifests)
- Add README with layout and deploy commands

mysql-chart/templates/statefulset.yaml

@@ -1,6 +1,6 @@
 apiVersion: apps/v1
 kind: StatefulSet
-metadata: 
+metadata:
   name: mysql
   namespace: {{ .Values.namespace }}
 spec:
@@ -15,15 +15,20 @@ spec:
       containers:
       - name: mysql
         image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
+        envFrom:
+        - configMapRef:
+            name: {{ .Values.configMap.name }}
         env:
-        - name: MYSQL_DATABASE
-          value: {{ .Values.mysql.database }}
-        - name: MYSQL_USER
-          value: {{ .Values.mysql.username }}
         - name: MYSQL_PASSWORD
-          valueFrom: {secretKeyRef: {name: mysql-secret,key: MYSQL_PASSWORD}}
+          valueFrom:
+            secretKeyRef:
+              name: {{ .Values.secret.name }}
+              key: MYSQL_PASSWORD
         - name: MYSQL_ROOT_PASSWORD
-          valueFrom: {secretKeyRef: {name: mysql-secret,key: MYSQL_ROOT_PASSWORD}}
+          valueFrom:
+            secretKeyRef:
+              name: {{ .Values.secret.name }}
+              key: MYSQL_ROOT_PASSWORD
         volumeMounts:
         - name: mysql-data
           mountPath: /var/lib/mysql