[e.cash] Fetch exchanges and services and render on get ecash page

Summary: Adding the list of exchanges and services to the get ecash page. The data is being pulled from the scorecard.cash api using the recently added methods, and sorted on the same scoring criteria that scorecard.cash uses so better services are listed first

Test Plan:
preview the site and go to the get ecash page
check everything looks good and all the links work

Reviewers: #bitcoin_abc, bytesofman, Fabien

Reviewed By: #bitcoin_abc, bytesofman, Fabien

Subscribers: Fabien, bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14025