refactor: use URLSearchParams to manage params

[cdeery]

Instead of managing URL parameters by hand, use the URLSearchParams feature.
This will help with future work managing additional parameters in the future.

[jsnwesson]

LGTM! My one nitpick is that the URL param itself is 2U_degrees (plural) but its counterpart is singular. If there's at least a note to explain the difference, that'd be great, but I also wonder why we don't just convert the param to be singular as well

[cdeery]

LGTM! My one nitpick is that the URL param itself is 2U_degrees (plural) but its counterpart is singular. If there's at least a note to explain the difference, that'd be great, but I also wonder why we don't just convert the param to be singular as well

Thanks for noticing. The difference between 2u_degree and 2u_degrees is a temporary change to "disable" the degrees LOB without having to modify prospectus. My preference would be to eventually simplify all of the query parameters, because they shouldn't have to be the same as the Algolia parameters.