New collective page initial release

[Betree]

This issue will track the progress for the first iteration of the new collective page.

Files

• All components specific to this page will go to components/collective-page
• index.js will export the main content component

Tree

└── components
⬜├── collective-page
⬜│⬜├── Hero.js
⬜│⬜├── index.js
⬜│⬜├── NavBar.js
⬜│⬜├── SectionAbout.js
⬜│⬜├── SectionBudget.js
⬜│⬜├── SectionUpdates.js
⬜│⬜├── SectionContributejs
⬜│⬜├── SectionContributors.js

Concepts

• The main component (index.js) will be responsible for tracking the scroll position and update children accordingly.
• For the first iteration, this page will be mounted on /collective/v2

Don't forget

• Migrate the old notification bar

Design

• Desktop: https://www.figma.com/file/e71tBo0Sr8J7R5n6iMkqI42d/09.-Collectives?node-id=0%3A7428
• Tablet: https://www.figma.com/file/e71tBo0Sr8J7R5n6iMkqI42d/09.-Collectives?node-id=2338%3A36062

[Betree]

The initial release is now ready, we'll use #2225 to collect feedback on it