chore(postgres): enlarge the postgres volume

Also resized the stage for the testing purposes, it ain't much(, but
it's an honest work), if we reserve a lot of resources on preprod, we
can relax it (we're using barely 300MB on stage).

Turns out that you, indeed, can resize the PVC with the pod running and
then just rescale the deployment (postgres).

Fixes packit#604

Signed-off-by: Matej Focko <[email protected]>

openshift/postgres.yml.j2

@@ -137,7 +137,7 @@ spec:
     - ReadWriteOnce
   resources:
     requests:
-      storage: "{{ '4Gi' if deployment == 'prod' else '1Gi' }}"
+      storage: "{{ '8Gi' if deployment == 'prod' else '2Gi' }}"
 {% if managed_platform %}
   storageClassName: aws-ebs
 {% endif %}