Add an optional chapter-specific project review date range

[divideby0]

This is somewhat related the issue listed in #251, but more generic for chapters that don't review within a calendar month. I'm working on a feature that allows chapter admins to maintain a common "project review" date range, so that when trustees review grants they get the start and end filters are pre-populated (but overridable). Each field would be optional and require a bit of housekeeping where the dean would have to manually update the range after each meeting, but we'd personally find it useful in the Chicago chapter. I'll submit a PR momentarily.