Add QR scan support for asserting antenna gain/elevation and hotspot transfer

[MichaelBrew]

Combo of https://github.com/helium/hotspot-app/pull/977 and https://github.com/helium/hotspot-app/pull/1342

JSON payload to re-assert antenna gain/elevation

{
  "type": "hotspot_antenna",
  "hotspotAddress": string,
  "gain": number,
  "elevation": number?
}

JSON payload to transfer hotspot

{
  "type": "transfer",
  "hotspotAddress": string,
  "newOwnerAddress": string,
  "skipActivityCheck": boolean,
  "isSeller": boolean
}