Update electricity consumption numbers for BTC

  - Updated KWh taken from the cited source's source
    (https://digiconomist.net/bitcoin-energy-consumption)
  - Updated number of days of french households based on the average
    consumption given by the Que Choisir association
    (https://www.choisir.com/energie/articles/104333/la-consommation-electrique-moyenne-des-francais-en-2020)