Request - Energy Costing

[jwhitbread]

Hi! Loving using this with Home Assistant. I currently have the P110 which can calculate costing, however it seems that it doesn't pull this information. I tried to make a branch and pull request, but I don't have perms.

I added to energy_info.py:

current_cost: float = property(lambda self: self.info["electricity_charge"][2])

which will return ..., current_cost=1173... - I think this will be a nice addtion to have in so it can be easily viewed in Home assistant.

Thanks,

Jordan.