Make performance-dashboards disconnected friendly

[akrzos]

I am unsure if there was a specific design reason to put git cloning as a script into the syncer container image however this makes performance-dashboards incompatible with environments that can not reach github.com. Could we put the templates directly into the container image or git clone but fallback to templates in the image instead of always trying to pull down the latest master branch?

[smalleni]

@jaredoconnell Is this something you could potentially looking into.
cc: @mkarg75 for visiblity/JIRA tracking :)