[FR] - Firebase Admin Lite

**Is your feature request related to a problem? Please describe.**
Currently Firebase cannot run on Deno, Cloudflare, Vercel Edge, or Bun (among others). Firebase will mainly be used in Node Serverless environments with Cold Starts, which are unacceptable for many app developers.

**Describe the solution you'd like**
If you don't require Authentication, you can use the "Firestore Lite" package. However, we cannot use Authentication or the Server Functions in order to keep our session. This is a HUGE problem and limits where Firebase can be deployed.

**Describe alternatives you've considered**
Using the REST API. However, it is EXTREMELY cumbersome in order to convert JSON data to the data types that REST API uses, as well as the problems handling tokens etc.

**Additional context**
- https://github.com/firebase/firebase-admin-node/issues/1879 - This should have been reopened, but never was.
- https://firebase.uservoice.com/forums/948424-general/suggestions/48355772-firebase-admin-lite - User Voice Feature Request

It would be nice to be able to use the [FirebaseServerApp](https://firebase.blog/posts/2024/05/firebase-serverapp-ssr) as well, but this would not have ALL the features we may need in other JS environments.

J