Dynamically retrieve course prefix list for coursebook scraping

[jpahm]

Currently in the coursebook scraper, the list of course prefixes is hardcoded in the form of an array named coursePrefixes defined at the end of the file. While this works for now, it isn't exactly the best solution since the school could presumably add more course prefixes at some later date.

Thus, to make this system more future-proof, we should retrieve the list of available course prefixes dynamically via scraping them directly from the coursebook prefix dropdown.

[mohammadmehrab]

I'd like to be assigned this issue please!

[jpahm]

I'd like to be assigned this issue please!

You got it!

[jpahm]

@mohammadmehrab Are you still working on this?

[jpahm]

**Disregard previous message

[jpahm]

Closed via #35