Use a shared database cache. Fixes #803.
Use a shared database cache. Fixes #803.

The default was a local memory cache, which was fast, but led to discrepancies
in each app's cache.

DXCanas/content-curation,DXCanas/content-curation,fle-internal/content-curation,jayoshih/content-curation,fle-internal/content-curation,DXCanas/content-curation,jayoshih/content-curation,fle-internal/content-curation,jayoshih/content-curation,jayoshih/content-curation,fle-internal/content-curation,DXCanas/content-curation