[e.cash] Add Swapzone widget

Summary: Adding the Swapzone widget to the /get-ecash page

Test Plan:
Preview the site and navigate to /get-ecash. check below the exchange listings for the swapzone widget. Check everything
looks good and functions properly

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14580