Create custom entity for metastore

[dafeder]

Build out a custom entity with bundles to replace the "data" content type in Drupal.

Acceptance criteria

• On enabling module, there is a custom entity for metastore items and bundles for schemas
• Clear admin interface that is at least as intuitive as existing node one.
• All DKAN functions work seamlessly with new entity system.
• I can see readable titles for all my metadata so that I can find what I'm looking for.
• Hashes are storable and retrievable. This will be done in #3465 so this ticket can't be merged until that's done.

Estimate:

2 days

[dafeder]

I've gotten pretty far with this but the acceptance criteria are blocked by #3444. Putting this aside until that's been done. This may actually be complete and just need the lifecycle and reference work to start passing tests.

Once #3444 is in this should take no more than 1 day to complete.

[ghost]

From Dan: Finishing #3321 is too ambitious for the timeline that we have (we’re 75% there). We should deprioritize this one and write up another ticket to do the admin work that is absolutely necessary for this sprint. This new ticket can be done today.