Add "Help" or "About" section to html-app

[jdaguil]

Narrative: I want to see be able to find "Help" information about the ScanCode scan results and UI within the html-app.
Context: The html-app does not have description about the different tabs, filters, etc or other documentation that would be helpful to the user.
Acceptance Criteria:
- Scenario 1: A user should be able to access documentation about the html-app and scan results within the html-app.

[mjherzog]

Part of the help system should be a link to new Wiki pages on GH where we provide several "How To Interpret the Data from ScanCode" examples using sample scans.