feat:create-navigation-button

[sammyrolfe]

Description

Added option to header dropdown menu for navigation to the coursemap page.

Fixes # (issue)

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested navigation with button and rendering landing page correctly with multiple browsers.

Testing Checklist:

• [] Tested in latest Chrome
• [] Tested in latest Safari
• [] Tested in latest Firefox

Checklist:

• [] My code follows the style guidelines of this project
• [] I have performed a self-review of my own code
• [] I have commented my code in hard-to-understand areas
• [] I have made corresponding changes to the documentation
• [] My changes generate no new warnings

[sylvia0929]

Tested navigation and landing page rendering across multiple browsers.
Checklist items look good. Code style and comments are clear. No new warnings introduced."

[DudeUnleashed]

Everything tested and works as intended, new button links to the appropriate new page ready for future courseflow.
Code looks good, comments are clear and no new warnings are introduced with this addition.

[aNebula]

Good work this trimester @sammyrolfe - time to make your contributions 'lasting'.
Please open an upstream PR with these changes against new/course-flow branch on doubtfire-lms/doubtfire-web.