Default time frame for data collection

Most of the CHAOSS-related metrics need data that is recent in time. If the platform collects all the data available for all the analyzed projects, it may add a lot of information that 1) is not useful and 2) may add extra overload to the platform. From my point of view, the platform should allow the user to obtain only the most recent data.

My proposal is to allow the operator/user to set a default time frame, so that the platform collects the events for the monitored projects after that date and not before.