Add custom landing page for Help (#531)

Includes:
- Updated the Step component to use the label field instead of title, and to accept children
- Added a custom Help landing page (hiding the bottom section in production)
- Hiding the rest of the pages of the Help app in production
- Allow users to see the help landing page in production (links on the Home page and in the launchbar)
- Fixed the styles on the About page
- Hiding the Custom Download button in the launchbar in production
6 jobs for update-help-link in 4 minutes and 38 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Setup
passed #514235
SetupReview:HX

00:00:12

 
  Test Build Static
passed #514236
Test_N_Build:review

00:03:24

 
  Build Docker Images
passed #514237
Nginx:review

00:00:49

passed #514238
Node:review

00:00:53

 
  Deploy
passed #514239
Review:HX

00:00:06

manual #514240
allowed to fail manual
stop_review