GitLab

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

Plus some refactoring to reuse the same components across Help app, contextual help, and About Ensembl.