Replace all make commands by a single "tutor" binary. Environment and
data are all moved to ~/.tutor/local/share/tutor. We take the
opportunity to add a web UI and revamp the documentation.
This is a complete rewrite.
Close #121.
Close #147.
This allows us to deploy much faster: all we have to do is to copy the
assets from the container to the shared volume.
We also changed the way themes are managed: similarly to static assets,
they are now packaged inside the docker image.
We no longer run the `configure` script on the host. Instead, we run a
container that generates the configuration files. This opens the way for
more complex configuration templates that would be written in jinja2.
More complex templates are required for feature flags, such as SSL,
XQUEUE, etc.
