Upgrade Bootstrap v5 (+ Font Awesome v5)

[thescientist13]

Coming out of the conversation in #60, In the interest of staying up to date with key dependencies, I would be open to evaluating the benefits of upgrading to the latest version of Bootstrap, with the presumption being that it dropping support for IE and other technical enhancements, that at least the following would improve:

1. bundle size goes down
2. Performance goes up (or at least stays the same)

It would be great to have someone evaluate Bootstrap v5 (and FA v5 while we're at it) to understand:

1. Breaking changes / impact to upgrade
2. Relative LOE
3. Potential improvements to perf and bundle stats