This diff introduces the usage of the Expo `BarCodeScanner` when the header right 'Add' is clicked on the linked devices screen.
The [[ https://docs.expo.dev/versions/latest/sdk/bar-code-scanner/ | Expo docs ]] were closely followed in setting this up.
For now, the `onConnect` will not do anything besides alert the user that the qr code has been scanned with the data encoded, but down the line this will be changed to read the secondary devices' keys encoded in the qr code.
Addresses both [[ https://linear.app/comm/issue/ENG-4475/use-the-expo-barcodescanner-library-to-read-qr-codes-from-within-the | ENG-4475 ] and [[ https://linear.app/comm/issue/ENG-4477/alert-the-primary-device-when-the-qr-code-is-scanned-with | ENG-4477 ]].
Depends on D8771