Add randomness to matcher algorithm

[edwardneo]

Currently, the matcher tends to output the same tiebreak, but we would prefer some variety between courses and section times for easier room bookings. There are some solutions to this (consider matcher runs from courses already done, randomize the output without seeding), but the likely best solution is to randomize tiebreaks using the course ID as a seed to consistently output the same schedule for the same course but a different schedule for a different course, even if the courses have the same preferences. Although this doesn't guarantee the least scheduling overlap, in expectation this should help room booking.