[Feature] Add ability to include/exclude groups from stats

# Overview

Currently, the admin-side Stats at a Glance page displays the information of all users of HackPortal. This limits the information hackathon organizers have in regards to how many _hackers_ got swag or food or what their demographics were, instead of anyone with an account or organizer info being added to the data.

# Proposal

There should be options to include/disclude certain people's stats from showing up in the data.
The options should include Admin, Super Admin, Hacker (these are people who have checked in and are not admin), and all accounts.

# Supplemental Information

Example of issue:
141 hackers checked in (no way to differentiate checked-in admins from hackers).

Organizers may want info on just hackers who have checked in, not everyone with an account. This is an example of the data being displayed for everyone with an account.