Rework the artifact endpoint, making it similar to the CLI invocation.
It now works on a single artifact and can be made to return both `json`
and `tar` as formats.
Now containers can be dump and loaded in both yaml and tar. Also the
container can automatically try to figure out the format of the
container. Moreover, now containers have to_bytes and from_bytes.
Add implementation of the generic pype daemon.
It's implementation is split into `daemon.py` where we implement an
http framework agnostic interface, and `app.py` that uses it to serve
them using starlette.
Giacomo Vercesi