Some reportcards need weekly granularity. Today they are implemented as non-timeboxed reports using generate.py.

However, to comply with the EventLogging audit, all reports based on purged schemas need to be timeboxed. And timeboxed reports do not support the weekly granularity hack. So weekly granularity must be implemented as a core feature of the scheduler. And as we are not maintaining generate.py any more, we'll do that on reportupdater.