Add admin interface

[tobiasdiez]

Motivation: we need a simple admin interface to e.g. check what data is currently present in the database. At the moment, this is especially helpful to check our azure setup.

Current version: https://app.forestadmin.com/JabRefOnline/Development/Operations/data/_prisma_migrations/index

Docs: https://docs.forestadmin.com/beta-developer-guide-agents-v2/
Admin: https://app.forestadmin.com/JabRefOnline
Alternative considered: https://adminjs.co/, but this brings in all the react dependencies

Next step: fix https://github.com/tobiasdiez/nuxt-forestadmin/issues