feat(prisma): use root .env + remove npx

[Oupsla]

Hello @marcjulian

Last PR about .env files 😄

2 changes :

• Use dot-cli to include root .env file to use prisma (so no need to have 2 .env files and to sync them)
• Remove npx to invoke prisma, since prisma-cli is included in devDeps (correct me if I'm wrong about that, but npm seems to find the correct prisma cli in node_modules and don't need to download prisma cli again with npx)

Nice weekend 👋