Add summary reports showing testing center usage

[mwest1066]

As requested by Lynn Phillips, add reports on reservations as follows.

By exam

Aggregations:

• reservations_by_exam.csv: Columns course, exam, and reservation counts.
• reservations_by_course.csv: Columns course and reservation counts (rollup of the above).

Reservation counts include:

• reservations: Number of students who had a reservation at some point.
• exams taken: Number of times a student started an exam (can happen more than once per student).
• no shows: Number of times a student was a no-show (can happen more than once per student).
• repeats: Number of times a student started an exam they had already previously started (can happen more than once per student).
• cancelations: Number of students who had a reservation at some point but canceled it before the exam and never took the exam.
• rebookings: Number of times a student changed their reservation in advance of the exam (can happen more than once per student).

By session

Aggregations:

• reservations_by_session.csv: Columns date, time, location, seat_group, and slot counts.
• reservations_by_day.csv: Columns date and slot counts.
• reservations_by_seat_group.csv: Columns location, seat group and slot counts.
• reservations_by_location.csv: Columns location and slot counts.

Slot counts include:

• capacity: Number of seats available.
• exams taken: Number of reservations linked via a seat hold that started the exam.
• no shows: Number of reservations linked via first_session that were deleted after the first session start, or which never started.
• future usage: Number of reservations linked via a seat hold, for sessions in the future.
• predicted usage: Number of predicted slots.

For the aggregated views (by day, by location, etc), also include unique reservation counts as well as per-slot counts.

[Jim-Sosnowski]

In addition to what is listed above it would also be helpful to have:

• additional aggregation for students with accommodations
• a way to identify how many students in each course have testing accommodations
• information about how far in advance students make their first reservation for an exam

This document is a sample report that UC San Diego can generate with a scheduling tool that they use for paper-based exams. Being able to generate a report similar to this would be helpful. https://docs.google.com/spreadsheets/d/1h22YJwONL046cG4hQrzWBuE4-VgpF7Sm/edit?gid=1842071202#gid=1842071202

[Jim-Sosnowski]

Data related to how students are interacting with PT (making / moving / deleting reservations). Basically a data dump of student logs so that we can analyze student behavior.