Add a new field to scheduled courses

**[Original report](https://bitbucket.org/laborstudents/cas-flask/issue/345) by Scott Heggen (Bitbucket: [sheggen](https://bitbucket.org/sheggen), GitHub: [sheggen](https://github.com/sheggen)).**

----------------------------------------

Courses that are scheduled have two loads: Course load credit \(what we currently store: 0.25, 0.5, 1, etc\) and faculty load credit \(new\).

Scott would like to add a field for department chairs to indicate both these values when scheduling a new course. This new value will be stored in the courses table as a new column, and exported with the spreadsheet. It would also need to be added to the edit modal, and possibly the courses table.