[website] Add ViaWallet explorer to site

Summary: Found another explorer for BCHA

Test Plan:
Checked out the explorer to make sure it agrees with others, and local node
Built and ran the site locall to see that it looks good, and link works.

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D8995