Resolve "Password iframe gets blocked by browser"

Addresses #68 (closed)

This MR deploys the code to apps.learn[.staging].totem-project.org instead of the old place we deployed them. We used to have a reverse proxy on learn.totem-project.org that proxied requests to where we deployed these on a hosting package, but now the js components need to live in the same domain as the MFEs, which are actually already hosted on that same hosting package.

So now we deploy to the MFE subdirectory in the hosting package, and we can remove the reverse proxy plugin called totem-proxy from tutor-server repo (tutor-server#104 (closed)).