[Improvement] Add PayId source in search result screen

[WietseWind]

The search result screen gets an update with source;
#26

Add "PayId" source as well, eg.

• https://xumm.app/api/v1/app/handle-lookup/%24wietse.com%2Fquinn
• Response:

{
  "input": "$wietse.com/quinn",
  "live": true,
  "cached": 1586043165,
  "explicitTests": {
    "emailAddress": false,
    "xrplAccount": false
  },
  "matches": [
    {
      "source": "payid",
      "network": null,
      "alias": "Wietse Wind",
      "account": "rBabyRPDAdHe5U84n7YV7iQuWhgic8vNq6",
      "tag": null,
      "description": "$wietse.com/quinn"
    }
  ]
}

(Linked to: #102 for implementing QR based PayId)

[WietseWind]

Already live at backend, manual entry returns result: