Swapping icons to Font Awesome, improves icon accessibility (#148)

Concisely, this PR does a couple of things:

* we install [Font Awesome](https://fontawesome.com/) and its related react dependencies
* we replace all SVG icons (social media + committee logos) with Font Awesome icons (individual imports w/ tree-shaking)
* we add `aria-label` tags to make icon links accessible
* we delete now-irrelevant CSS + icons from the `public/` folder

This PR is related to three issues:

* closes #94 and closes #146
* is a required precursor to #136 (due to the current icon implementation relying on the `public/` folder)

The components/pages we hit are:

* the footer's dark `<SocialMedia/>` CTA, which is on every page - needed to also adjust some in specific CSS
* the light `<SocialMedia/>` CTAs on the home page and the about page
* the committees page (swapping out committee logo links for a link icon)
* the event page (by swapping out an icon in favour of text)

And some other relevant notes:

* I took a bit of liberty in adjusting what I felt were unclear links (i.e. changing a committee logo to a link logo for the website, removing the YouTube link on events in favour of the word, etc.)
* I also changed link hover behaviour: instead of previously applying a very small scale-up (`1.02`), I change the color of the link. I feel that this is easier to see (and thus more accessible), plus causes less layout jank.
* FA resolves all the weird SVG issues (notably, the Discord icon)
* compared to a full-on rewrite (which may come down the line), this PR looks to do in-place refactoring. Notably, I don't create any new (external) components (i.e. a unified icon-link). This is something we could explore down the line, but I didn't want to bloat this PR.

Let me know what y'all think 😊

Author: mattxwang

package-lock.json

@@ -3,6 +3,10 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
+    "@fortawesome/fontawesome-svg-core": "^1.2.35",
+    "@fortawesome/free-brands-svg-icons": "^5.15.3",
+    "@fortawesome/free-solid-svg-icons": "^5.15.3",
+    "@fortawesome/react-fontawesome": "^0.1.14",
     "@testing-library/jest-dom": "^4.2.4",
     "@testing-library/react": "^9.3.2",
     "@testing-library/user-event": "^7.1.2",