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.
Portainer is no longer a global activation flag, because it does not
make much sense in the context of kubernetes. Instead, we use a simpler
"make" command.
