Wishlist: reporter should allow "this org + descendants" capability

Currently, when selecting a list of organizational Units for reports filters from a list, the user must click on all units under a system, which can be cumbersome. It also does not allow for reports based on hard-coded filter selections of org units that may be added or removed between runs. I propose we create a feature in the reporter that leverages the actor.org_unit_descendants function in the Evergreen database that equates to "this org and all its descendants". Example usage: "SELECT id FROM actor.org_unit_descendants(1);" returns all org IDs under a parent unit including the parent and doesn't need to care about whether we have new orgs or not, allowing easier re-use of previously-created reports.