[ENH]: Add new energyprice provider energy-charts.info

[NormannK]

Link to discussion and related issues

replace akkudoctor energyprice api by energy-charts.info
https://api.energy-charts.info/#/prices/day_ahead_price_price_get

Proposed implementation

basically copy ElecPriceAkkudoktor to ElecPriceenergycharts

[NormannK]

can be done in combination #365
if tibber is used tax values should be set/checked by tibber data and energy-charts.info can be used as fall back information.
maybe even if there is more up to date data available there.

[b0661]

Do Not replace, but add a new prediction. Sich you can Switch predictions by config.prediction_provider.