Clean up API elements

* define fastapi routes in routes.py instead of main.py (?)
* define an entry point to start uvicorn at gene_norm_serve or something to that effect (or maybe provide different CLI options for gunicorn/uvicorn/etc)

Start by reading main.py and routes.py to understand how the FastAPI routes are currently defined and how the service starts. Review the package entry points and the possible uvicorn or gunicorn CLI approaches; done means the route definitions and service startup are organized as agreed without changing the service interface.

Written by the indexing model from the issue text.