Support building large images in DinD container

[jrbe228]

Store docker image layers in ephemeral PVC to avoid pod eviction due to exceeding storage limits.

This change allowed our organization to build larger docker images (>50GB).

[alec-drw]

FWIW our org does this today for both the docker volume and workspace

      volumes:
      - name: tool-cache
        persistentVolumeClaim:
          claimName: tool-cache-enterprise-runnerset-0
      - name: work
        ephemeral:
          volumeClaimTemplate:
            spec:
              accessModes: [ "ReadWriteOnce" ]
              storageClassName: "csi-ceph-rbd-xfs-flash"
              resources:
                requests:
                  storage: 100Gi
      - name: var-lib-docker
        ephemeral:
          volumeClaimTemplate:
            spec:
              accessModes: [ "ReadWriteOnce" ]
              storageClassName: "csi-ceph-rbd-xfs-flash"
              resources:
                requests:
                  storage: 150Gi