feat: add pilot database and router

[Robin-Van-de-Merghel]

Split of #421 , first part : pilot management

closes #960

[fstagni]

First review.

[Robin-Van-de-Merghel]

Where an issue?

Whether we have a base router with require_auth or not, we won't be able to override it in its children (cf #417 ).
So for pilots we must have require_auth=False at the base router because of secret-exchange. But now every pilot endpoint is opened.

Possibilities

Splitting

Let's start with the routers themselves. We can separate pilots and users endpoints : /api/pilots (only for pilots) and ~/api/pilot_management (only for users).

That brings us:

1. Cleaner: each their own territory, no overlapping, easier to read (you know that on /pilots its only pilot resources)
2. More secure: we can add a dependency to the pilot router (same as verify_dirac_pilot_token but for pilots)
3. We can have require_auth for /pilot_management, and enforce tokens

Using another approach

We could have a bare base router without dependency injection, with sub routers with verify_dirac_access_token:

# Authenticated parent router
protected_router = APIRouter(dependencies=[Depends(verify_dirac_access_token)])

@protected_router.get("/secure")
def secure_route():
    return {"msg": "secure"}

# Public sub-router (no auth)
public_router = APIRouter()

@public_router.get("/public")
def public_route():
    return {"msg": "public"}

Its goal would be to replacer DiracxRouter by fixing the issue, and keeping an explicit depedency injection.
Or have @router.authentificated.get(...) instead of @router.get, to explicitely say if we want auth or not