Add billing information and totals sensors

Note

The billing feature is experimental - some information may be better as sensors instead of attributes, which in nature are not stored as historical data.

Create an issue on the integration repostitory if you have ideas on how to make it better.

Changes

This release adds 5 new sensors:

• sensor.eforsyning_energy_use_prognosis
• sensor.eforsyning_energy_total_used
• sensor.eforsyning_water_use_prognosis
• sensor.eforsyning_water_total_used
• sensor.eforsyning_amount_remaining

Also added is new data in the attributes:

Billing: 
  Date
  MWh_Price
  M3_Price
  Amount_MWh
  Amount_M3
  Amount_VAT
  Amount_Total
  Amount_Paid
  Amount_Remaining

With the new sensors and attributes it would be possible to construct graphs on the actual cost of consumption as well as plotting the 'ceiling' the consumption is headed for. If the ceiling changes up/down you can see when changed use patterns have the right (or unwanted) effect.

Removed are the attributes for ENG2 and TV2. These attributes have little to zero value for a consumer, as they express energy transfer from and to the regional heating pipes in [M3*T] and can be used to calculate the temperature drop (and hence energy consumed). There are already more suitable values for this in the other sensors.

Full Changelog: v0.11.2...v0.12.0