app: redirect to ?auth should include &redirect-uri-after-auth=https://app.bringyour.com/xxx

[xcolwell]

Issue:

Deep links to add devices and redeem balance codes might require a login before working. The redirect-uri-after-auth parameter will redirect the auth page to an app url.

Solution:

When the web app redirects to https://bringyour.com/?auth, it should include a url to redirect to after authentication.

The redirect url should be absolute, e.g.

https://bringyour.com/?auth&redirect-uri-after-auth=https://app.bringyour.com/xxx

The URL will also need to be query parameter encoded of course.

[ahussain3]

This is addressed in #33