[WEBSITE] Add chinese version of the BCHD SLP post

Summary: Similar to D7218 but for the BCHD SPL post.

Test Plan:
Built it locally, navigation and image works. Not tested the rendering
as I don't have chinese fonts.

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D7248