Convert site from Bootstrap4 to Bootstrap5

[itsthejoker]

Relevant issue: #145

Description:

Since we started working on this so long ago, it still uses bootstrap4 -- it's better to change over sooner rather than later so that we have fewer things to break. This PR:

• removes bootstrap4
• expands the generic form
• adds error handling views for 404 and 500
• fixes Plausible.js metrics loading
• fixes navbar support for engineering blog
• fixes navbar support for mobile

Turns out that adblock lists are literally just looking for a script called plausible.js, no matter where it's loaded from -- so on the recommendation of Plausible, we'll now self-host the script and I've changed the name to potentially.js, which, hilariously, is enough to make it load. I've also disabled it if you're logged into the site, since we don't really want to track page views on the edit pages.

Screenshots:

Homepage:

Example page:

New form:

Engineering main page:

Engineering blog post detail:

Also adds a new feature where the name dynamically collapses on the engineering blog side for desktop -> tablet -> mobile.

Desktop:

Tablet:

Phone:

Checklist:

• [x] Code Quality
• [x] Pep-8
• [ ] Tests (if applicable)
• [x] Success Criteria Met
• [x] Inline Documentation
• [ ] Wiki Documentation (if applicable)

[TimJentzsch]

Just putting this comment here as a reminder to remove the testing form from the code

[itsthejoker]

Note to self: when this is deployed, we will have to manually fix the donations page.