[b58-ts] Set up CI publishing

Summary:
Add Dockerfile and changelog.

A release candidate has been published to secure the namespace. I'll update CI to match other publish methods before landing.

Test Plan: docker build -f b58-ts.Dockerfile -t b58-ts_local .

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D17262