Purchase ZCHF Link to Mt. Pelerin in Secondaries Widget

[luziusmeisser]

Today, the secondaries widget looks as follows if there are not sufficient ZCHF in the users wallet:

Instead, there should be a button like this:

When the button is clicked, a new dialog like this should open:

As soon as the web app has received the signed message, the user is forwarded to the buy page of Mt. Pelerin, with his address connected. There, he needs to authenticate using his phone number and if the amount is greater than 1000 CHF, needs to go through the KYC process.

[luziusmeisser]

The API specification for creating the full link to Mt Pelerin can be found here:

https://developers.mtpelerin.com/integration-guides/web-integration

We should fill in all the data we know about the client. Most important are: ethereum address (with signed verification), desired amount of ZCHF, phone number.