Remove unused persistent volumes

Since we no longer have staging environments, we definitely don't need staging solr volumes, and we may have replaced the solr instances for the other environments as well (confirm w/@welp)

Original ticket:

Description:

Created by #77 (closed)

persistentVolumes used by solr services in lark-staging, lark-prod, and shoreline-staging should have storageClass upgraded to ebs-sc.

alternatively, we could migrate these indices to the shared dld-search solr stack along with shoreline-production in #87.