Affinity section popup and descriptions

[smartspot2]

Currently, the only way in which we can specify affinity sections are through a (poorly named) description field within a section. This offers little to no clarification on what exactly the affinity section is for, and as a result several students have enrolled in the affinity sections without knowing what they are.

Adding a popup when trying to enroll in an affinity section would help inform students on what the affinity section is, reducing these accidental enrollments.

To build more on section labels, we can also rework the section descriptions to allow for a better labeling system for sections, rather than a free-form text box for each section.