ci(docker): add Docker publishing workflow and Dockerfile

Introduce GitHub Actions workflow for automated Docker image
publishing to Docker Hub, along with a dedicated Dockerfile in
the ci directory to streamline container builds.

.github/workflows/docker-publish.yml

@@ -2,7 +2,7 @@ name: Publish Docker image
 
 on:
   push:
-    branches: [master,  ci/docker-hub-publishing]
+    branches: [master]
   release:
     types: [published]