chore: setup prod deployment (and cfg stg db creds)

.gitignore

 .gitsecret/keys/random_seed
 !*.secret
-backend/k8s/overlays/stg/database.secrets.env
\ No newline at end of file
+backend/k8s/overlays/stg/database.secrets.env
+backend/k8s/overlays/prd/database.secrets.env

.gitsecret/paths/mapping.cfg

-backend/k8s/overlays/stg/database.secrets.env:b292610d7ad4825d3b934bb69aaa7b72f8cad412ef6c572a58c7f07b549ac206
+backend/k8s/overlays/stg/database.secrets.env:20315cecd8ffc0b934acfdd6fc7b5c8761a9f7324f61b22df655e9897f97df62
+backend/k8s/overlays/prd/database.secrets.env:21029ab07d6110a9bfc1b641bb921c7cd6344a4894f87033a79bc9b1955644df

backend/k8s/overlays/prd/database.deployment.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: oetzit-database-deployment
+spec:
+  template:
+    spec:
+      containers:
+        - name: pg
+          env:
+            - name: POSTGRES_DB
+              valueFrom:
+                secretKeyRef:
+                  name: oetzit-database-credentials
+                  key: database
+            - name: POSTGRES_USER
+              valueFrom:
+                secretKeyRef:
+                  name: oetzit-database-credentials
+                  key: username
+            - name: POSTGRES_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: oetzit-database-credentials
+                  key: password

backend/k8s/overlays/prd/kustomization.yaml

+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+  - ../../base
+  - webserver.ingress.yaml
+namespace: kommul
+commonLabels:
+  eurac.edu/environment: prd
+  app.kubernetes.io/part-of: oetzit
+  app.kubernetes.io/managed-by: kustomize
+patchesStrategicMerge:
+  - database.deployment.yaml
+  - webserver.deployment.yaml
+images:
+  - name: oetzit-webserver-image
+    newName: gitlab.inf.unibz.it:4567/commul/oetzit/backend
+    newTag: main
+secretGenerator:
+  - envs:
+      - database.secrets.env
+    name: oetzit-database-credentials
+    type: Opaque

backend/k8s/overlays/prd/webserver.deployment.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: oetzit-webserver-deployment
+spec:
+  template:
+    spec:
+      containers:
+        - name: oetzit
+          imagePullPolicy: Always
+          env:
+            - name: DATABASE_URL
+              valueFrom:
+                secretKeyRef:
+                  name: oetzit-database-credentials
+                  key: url

backend/k8s/overlays/prd/webserver.ingress.yaml

+apiVersion: extensions/v1beta1
+kind: Ingress
+metadata:
+  name: oetzit-webserver-ingress
+  annotations:
+    ingress.kubernetes.io/rewrite-target: /
+spec:
+  rules:
+    - host: kommul.eurac.edu
+      http:
+        paths:
+          - path: /oetzit
+            backend:
+              serviceName: oetzit-webserver-service
+              servicePort: 80