✨ API Token support + extra price sensors

Mirror of official HA-Core integration 'pvpc_hourly_pricing', with proposed changes to

• support authenticated access with ESIOS API Token,
• and enable more electricity price sensors, like the 'injection price' for solar installations ☀️

Pushed here to enable beta testers to install it through HACS until review process is finished,
and final changes are released in HA 🤞