Make instascan QR scanner work on iOS

[bfirsh]

We want to use https://github.com/schmich/instascan for scanning QR codes, but it doesn't seem to work on iOS.

All the APIs seem to be in place, but something doesn't seem to be plumbed up correctly. It asks for permission, displays a camera icon in the URL bar, but then doesn't actually display anything on the screen.

See also #25.

[rubenspgcavalcante]

So after going thru the open issues, it seems instascan development is a little inactive. Some people already asked about updating the webRTC package of the lib so it can work on iOS devices

There's a plenty of PR's stacking too, so maybe even if we try to do one, we'll need to wait a while :(

[bfirsh]

Looks like we could just fork it though! schmich/instascan#112

[rubenspgcavalcante]

At least I've put instascan as per-dep. of react-instascan, so using it from the fork should work :)

[HaGuesto]

@rubenspgcavalcante can we close this issue?