Adds Prisma setup fn

[infomiho]

This PR enables users to override the default PrismaClient init and setup e.g. logging of SQL that Prisma is sending to the DB. It's also useful to add Prisma client extensions.

Left to do:

• Investigate if we need to adjust how we use the PrismaClient type (maybe we will need to infer the type from the user returned PrismaClient)
• Docs
• Add a test (probably headless test)
• Update the Typescript Spec

Closes #2116

[infomiho]

Either we use the default init, or the user defined init.

[infomiho]

The user defined init fn will return a type with more type info than just the plain PrismaClient

[infomiho]

I'm on the fence if it makes sense to provide this type:

1. we usually provided it and it enabled users to have some type safety (it would make sense to include it now as well)
2. the problem is that if the user extends the client with client extensions for some reason the returned type is incompatible with PrismaClient

const prisma = new PrismaClient({
  log: ['query'],
}).$extends({
  query: {
    task: {
      async findMany({ args, query }) {
        args.where = {
          ...args.where,
          description: { not: { contains: 'hidden by setupPrisma' } },
        }
        return query(args)
      },
    },
  },
})

// This is an type error ❌
const someOtherObj: PrismaClient = prisma

[infomiho]

We filter out all the tasks that contain this string. This enables us to test out the Prisma setup fn with headless tests. I couldn't come up with something better 🤷