Display price equivalent in currency

[coderofstuff]

TODO

• Retrieve price information from some source. Choices are:
  • api.kaspa.org (but only USD)
  • from CoinGecko
  • from CMC (?)
• Show the price equivalent of KAS
  • In Addresses tab
  • When sending (amount and fee)
  • In Transaction tab (limited to using current amount, since it's much harder to get historical data of price at time of TX)

Initial implementation will be only for USD (easiest path to implementation).

Follow-up work

• Allow user to select currency other than USD (may require updates to api.kaspa.org) - store this in user's settings and persist between reloads