[e.cash] Add get ecash page

Summary: Adding the layout for the get ecash page. Will add content next

Test Plan: preview the site and naviagte to /get-ecash. You should see the page hero. Check mobile and both themes

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14004