update the web socket support

[fabricedesre]

We need to hook up web sockets to the taxonomy watch_value api.
We discussed filtering which message a client can get based on a permission system. Since currently we only have an "admin" user that can access everything, the implementation of the message filtering will be very simple for now.

@mcav is that something you would be interested in?

[mcav]

Sure.

[fabricedesre]

For the record, @Yoric mentioned that the internal apis will change quite a bit with the decentralized taxonomy, so let's coordinate these.