Prisma Quickstart Guide documentation requires updates and migration guidelines for Prisma V7^

# Improve documentation ## Link https://supabase.com/docs/guides/database/prisma ## Describe the problem After the Prisma v7 release the `schema.prisma` file does not require the `DATABASE_URL` and `DIRECT_URL` in `datasource db {}`. Currently the documentation for [Prisma Quickstart Guide](https://supabase.com/docs/guides/database/prisma) mentions the deprecated `datasource db {}` format for the `serverless deployments` in `Step 3`. https://github.com/supabase/supabase/blob/90d383f182b25a8ea4aba82f125047903d6a0851/apps/docs/content/guides/database/prisma.mdx?plain=1#L173-L177 ## Describe the improvement The documentation for [Prisma Quickstart Guide](https://supabase.com/docs/guides/database/prisma) should have all steps aligned as per the latest standards introduced in `Prisma v7` while also providing compatibility/migration documentation for previous versions of Prisma. As per `Prisma V7` [documentation](https://www.prisma.io/docs/orm/prisma-schema/overview#accessing-environment-variables-from-the-schema): ```prisma datasource db { provider = "postgresql" } ```