Add option to customize the degree picker's program request per_page parameter

[cadie]

The per_page parameter for getting back the program requests for the degree picker could be a customizable theme setting:
https://github.com/UCF/UCF-Degree-Search-Plugin/blob/master/src/js/ucf-degree-picker.js#L86

We could default to a sane value, like 30, and allow it to be overridden if necessary.

We might also want to look at allowing overrides on the Interests request per_page param as well.