Cleaning up examples/ models and starter .env files (#1124)

Closes https://github.com/go-skynet/LocalAI/issues/1066 and
https://github.com/go-skynet/LocalAI/issues/1065

Standardizes all `examples/`:
- Models in one place (other than `rwkv`, which was one-offy)
- Env files as `.env.example` with `cp`
    - Also standardizes comments and links docs

examples/localai-webui/docker-compose.yml

@@ -8,8 +8,6 @@ services:
       dockerfile: Dockerfile
     ports:
       - 8080:8080
-    env_file:
-      - .env
     volumes:
       - ./models:/models:cached
     command: ["/usr/bin/local-ai"]