AAI-281 GUI admin for the AAI Backend database

[marius-mather]

Description

AAI-281: implement a GUI to view/manage the AAI backend's database, using https://aminalaee.github.io/sqladmin/ .

Changes

• Set up sqladmin against our DB
• Authenticate access to the admin using Auth0 roles (user has to have one of the roles configured in ADMIN_ROLES)
• Add our existing DB models to the admin (view-only permission for now)
• Unit tests of access/authentication to the DB

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have added unit / integration tests that prove my fix is effective or that my feature works
• I have run all tests locally and they pass
• I have updated the documentation (if applicable)

How to Test Manually (if necessary)

Run uv run fastapi dev and visit localhost:8000/db_admin: you must have ADMIN_ROLES set to include a role like biocommons/role/biocommons/admin in .env, and your Auth0 user account must have this role.