Dataset search (#18715)

* Move the multimethods over to strings not classes

datasets are Cards so don't have a good way to intercept. And this kinda
took all of the keywords, turned them into classes, and then didn't
actually use those classes-- they were just opaque keys in the
hierarchy. No bueno.

* Include datasets in search results

* Docstring for the linter. Thank you clj-kondo

* Fix namespace decls

* Update tests

* Clean up ns and make test more resilient

these tests that test global collections can be sensitive to test order
and the CI dbs that continually exist rather than be
recreated. Sometimes "table" shows up in these available models. Kinda
don't care so just check for subset

* Rename for confusion