Dockerfile: Delete build-time settings and secrets files.
Dockerfile: Delete build-time settings and secrets files.

Since these files are intended to be automatically generated by
entrypoint.sh at container startup time, these files are at best
useless and at worst could result in users ending up with copies of
the secrets generated when the Docker image they were using was built.

Galexrt/docker-zulip,Galexrt/docker-zulip,Galexrt/docker-zulip