Auto DevOps review apps should share PVCs
Description
Apparently GKE can only have 16 PVCs per node, yet each review app creates a Postgres pod by default, which creates a PVC. Perhaps we can share a single PVC for all review apps (of the same project?) and just use different subdirectories? It's not like they need a lot of disk space. Production apps should have isolated postgres PVC, of course.