Remove Bootstrap dependency

[solkaz]

Description

• Remove Bootstrap and its associated dependencies from the app
• Add style changes to accommodate the styling lost with removing bootstrap.

Motivation and Context

Fixes #491

Checklist:

• [x] My code follows the code style of this project.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.

Browsers

• [x] Chrome
• [x] Firefox
• [x] Safari
• [ ] Mobile:
• [ ] Other:

Screenshots (if appropriate):

Before (Chrome):

After:

[thebho]

Does this change anything with smaller window sizes?