Support disabling specific endpoints

Pyctuator now supports disabling specific endpoints such as "environments".
This is done by specifying the endpoints to be disabled as follows:

pyctuator = Pyctuator(
    app,
    "Example FastAPI",
    app_url=f"http://{example_app_address}:8000",
    pyctuator_endpoint_url=f"http://{example_app_address}:8000/pyctuator",
    registration_url=f"http://{example_sba_address}:8080/instances",
    app_description=app.description,
    disabled_endpoints=Endpoints.ENV | Endpoints.HTTP_TRACE
)