[e.cash] Roadmap layout improvements

Summary:
Responding to some feedback that the roadmap page design was not ideal. The a more simple approach like our current layout would be easier to digest.
So

• lose the horizontal scrolling
• reduce the size of the cards
• make the status more clear

Also adding the build page CTA at the bottom to round out the page

Test Plan: preview and check, compare with master

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D18644