Add a script to list RDO contributors in a period of time
Add a script to list RDO contributors in a period of time

As we take this information in every new release, let's get it into a
script at least for documentation purposes.

Change-Id: I521ceb9b2d6befde38416e248fbbabd970b47095

rdo-infra/releng,rdo-infra/releng