Default price info resolution to QUARTER_HOURLY

[peterpedron]

The proposed solution here
https://github.com/BeatsuDev/tibber.py?tab=readme-ov-file#getting-quarter-hourly-price-information
of querying quarter-hourly prices only works for past price ranges, tomorrow's prices are not avaialble on the range query (it appears to me)

This change makes the quarter hourly prices available on the today and tomorrow objects by the default instead of the hourly rate.

[tau74]

I would need the quarter hour data not only on the historical data, but also on the today/tomorrow data.

[ericbstie]

Although quarterly hour resolution is the most useful moving forward, I don't think we should break backward compatibility right away by changing the default value. The Tibber API will change the default value in the future when quarterly hour resolution is widely adopted. (https://developer.tibber.com/docs/changelog#:~:text=At%20a%20future,supplying%20the%20argument.)

Instead, I'll add a new method called fetch_price_info (different from fetch_price_info_range) and keep the price_info property on Subscription. This can be used to fetch todays and tomorrows price.