Support WAS URL handling

[kristiankielhofner]

Now that we have project JS client side, etc WAS URL handling will need to be updated.

Current in-progress thinking:

• Next.js build artifacts to go to static/admin in WAS FastAPI
• WAS updated to support CORS (with * out of box)
• WAS updated with StaticFiles and html=True
• Users can figure out how to get to the WAS admin URL in their environment
• For initial configuration for WAS WS URL use JS window location to get protocol, hostname, and port.
• Pre-populate WAS URL input field with some handling: if https, use wss. Otherwise ws, then hostname and port for either. With hosting API and UI out of FastAPI WAS only needs to listen on one port now.
• Allow user to override WAS URL in the event they have more complex network configurations where their Willow devices may need to access it via an alternative URL
• The WAS URL from the UI will need to get POSTed to WAS and stored so WAS can self-reference itself for OTA, etc
• We may need to implement sqlite or similar to store this data and additional data down the road