[Feature] Show/enter converted values from (most) fiat currencies from/to XRP (backend price feed)

[WietseWind]

dd XRP balance local Currency Conversion:

• API Endpoint (@WietseWind)

• Settings: set preferred local currency

• Home screen: tap/ swipe left/right on XRP + balance to switch between XRP / currency view

• Send flow: when entering non IOU (XRP) amount: allow entering in currency & convert (show) XRP

• Sign Request: if payment & if non IOU: show both XRP and local currency ~ estimate.

• TX Details screen: if Payment (in/out) and if non IOU (XRP) show the current fiat ~ estimate.

• Request button (also for Read Only accounts, 'Show QR code') panel: Share & Copy address button next to each other ('pill', attached?) and add a button: "Request with amount". Allow amount entry, toggle between XRP and configured fiat currency (just like at the Amount in Send Flow), convert to XRP (just like in Send Flow) and then show a QR with the destination + amount prefilled:
  https://xumm.app/detect/request:{myAccount}&amount={amountInXrp}

@thisistriss For you to take a look at:

• Send flow + Request:
  How are we going to allow a user to toggle (to enter an amount, when currency to send selected = XRP) between enter in XRP (to send XRP) or enter in local currency - A toggle under / above the amount field? A popout/option when focussing in the amount field, where users must select what they want to enter first? ..

Edit:
In the send screen having two input for XRP and Selected currency

[canny]

• This issue has been linked to a Canny post: Show current exchange rate and fiat value when sending/requesting a payment 🎉
• This issue has been linked to a Canny post: Create payment request with preset fiat amount producing a QR code for the equivalent XRP amount 🎉
• This issue has been linked to a Canny post: Show balance fiat value (like $) 🎉