Fix plantuml rendering of Nuxeo Stream Topology

It is possible to represent a Nuxeo Stream Topology as a component diagram using PlantUml.
But Computation or Stream names are not always valid PlantUml identifiers for node or queue, also a topology can have computation and stream with the same name which creates errors.

Some sanitizing must be done so the output simply works, adding more information about the computation policy will be useful.