Move some reused code into components

[MatthewStanciu]

Especially while building the new past-event.tsx pages (and its related components gallery.tsx, image-card.tsx, image-grid.tsx, and stats-card.tsx (honorable mention to desc-box.tsx, gray-card.tsx, and styled-button.tsx), I copy/pasted a lot of styling instead of making components, usually because the component involved conditional styling and I wanted to ship the project as quickly as possible.

Combining these styles into components is a bit harder than it sounds: because there's conditional styling involved, you need to make a component with base styling and use a library like tailwindcss-clsx, which is used to combine className strings for instances in which you need conditional styling, to add more styles to the components in other parts of the code.

It's probably not a few-minutes project, but it also shouldn't take too long, and it's a great first issue that would help me very much. :)