Added Department table and connected it with the User table
Replaced `User::__construct()` with `User::create()` which can take in a variable amount of arguments
Moved DROP PROCEDURE statements closer to where the procedure is defined
Update helper script
Added TimeOff table and related tables, stored procedures, and test data (refs #88)
Fixed issue where non-logged in users could access the professor page.
Remove trailing whitespaces in php, css, and html files
Admin course list (refs #90, refs #88)
Admin professor list (refs #88)
Admin time-off request list (refs #88)