Create inverter accessing endpoints

[ericcccsliu]

Create the following endpoints:

/sites/<site_uuid>/inverters

• Returns the inverter data from the inverters linked to this site. If there isn’t any, return a 404.

/inverters

• Returns the inverter data for all of the authenticated client’s inverters. 401 if not signed in.

Utilize the get_inverters_for_client function from pv-site-datamodel to get the inverters.

To access Enode, use httpx with a client to make requests to the endpoints above. You'll also need to get data from the database to determine the inverters for a specific site, by importing data models and making a query.

We'll have to create pydantic models for the inverter data responses. With datamodels, we can then write corresponding tests.