Drop Laminas DB dependency

There's a dependency on Laminas\Db, and public property in the Laminas module, but the adapter is never initialised. As the Laminas\Db project is effectively EOL (security-only), maybe it would be worth removing the dependency?

Start by locating the Laminas\Db dependency declaration and the public adapter property in the Laminas module. Confirm whether the uninitialised adapter is referenced elsewhere; done means the unused dependency and property are removed without leaving module references.

Written by the indexing model from the issue text.