Fixed date-to-year logic.
Fix db/fetch-game-chiptunes after column rename.
Refactored listing functions.

Refactored the org.ocremix.api.db listing functions into a generic fetch-listing function that also takes a table param.
Refactored some param parsing and db/fetch-listing boilerplate into an org.ocremix.api.listings/get-listing function.
Updated some listings' default sort fields.
Refactored entities functions.

Refactored some org.ocremix.api.db single fetch functions into a generic fetch-entity function that also takes a table param.
Refactored some entity ID existence check boilerplate into a org.ocremix.api.entities/get-entity-info function.
Refactored org.ocremix.api.db namespace.

Refactored the org.ocremix.api.db namespace into separate org.ocremix.api.persistence namespaces.