This patch add to tempest role, the generation of the report created by
stackviz from tempest results. Basically, what it does is:
- Download stackviz from git repository
- Copy static html and javascript stackviz files so we don't need
to install npm, download the dependences, and build the static html
(which would save some minutes)
- Install stackviz (only the processor)
- Run stackviz-export on tempest to collect the results
Also, add the code needed in the collect logs role to collect these
static files generated by stackviz.
Change-Id: Ia5ee717eaa9777bad265ecc338154e131021283f