feat: migrate to @pothos/plugin-drizzle

[Creaous]

Our types are currently being inferred from a select model in Drizzle and then passed into Pothos using Pothos' objectRef function. We should consider switching to the experimental Drizzle plugin that was added about 2 months ago.

[Creaous]

Attempted this during the rewrite, there are too many things to consider and I did not want to learn about the new relation API just to migrate it. When the new relation API moves out of beta, we will switch over to the plugin after a few months.