Added a chart legend for the weekday bookings chart

- There's now a nice little representation of which color line is which day in the top right corner.
- Most important, the landing page for our gen. stats looks even better now.
- Also commented out the text showing the day each line represents, since they were clumping up where the lines converged.
- NOTE: I basically just repurposed some code I found online, so tell me if it's inefficient the way I've done it.