feat: Implement 404 page

[farellukas]

Description

Implement 404 page, including setting up its route.

Required Items

• [x] Title matches [../CONTRIBUTING.md](contributing guidelines)
• [x] Linked Issue: #172
• [ ] Code Reviewed
• [ ] Manually tested
• Style
  • [ ] No Lint Errors
  • [ ] Quality Comments
• Tests
  • [ ] Unit Tests Added
  • [ ] CI/CD passes
• UI
  • [ ] Picture of before/after UI (if applicable)

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