Changes:
- Populate BottomBar.tsx and styles.scss with the relevant code required
to generate a bottom bar on screens less than 992px in width

Changes:
- Create a bottom bar folder and setup the required files
- Fix the top navigation bar styling (reduce height)

Changes:
- Update brand icon size to 40x40
- Add IBM Plex Sans in buttons and brand text
- Fix layout and centering of navbar elements
- Remove navigation pills and items

Note: Fixed an issue caused by breaking the link (to include IBM Plex
Sans) across multiple lines

Note: Added support for IBM Plex through the Google Font API.

Note: .DS_Store was added to the .gitingore (this file - "Desktop Services
Store" - is automatically created by macOS to store custom attributes of
the containing folder)

Description: Changed the border type such that the horizontal rule only
appears on the bottom and not all around the top bar.

Note: This only applies to the light mode concepts.

Changes:
- Create a README.md file in the concepts directory
- Add the concept images to a table in the README.md file

Changes:
- Create a new "concepts" folder
- Add four renders (course homepage and course view in dark and light
modes) to the concepts directory

Note: The "--template typescript" flag was used when creating the app
using yarn.

Description: Created a README.md file and populated it with a short introductory message describing the goal of the repository.