Clusterbuster: allow use of a single specified namespace

[RobertKrawitz]

Clusterbuster normally creates one or more workload workspaces and a sync workspace with names prefixed with the base name. It should be possible to optionally run all components within one workspace with the name of the basename.

This would be useful if someone prefers not to have multiple namespaces (or needs to run in a fixed namespace).

This will not be compatible with use of --namespaces >1. It may be implemented via --namespaces=-1 or similar.