After first release from `bazel` build, remove artifacts which were used in the old release process

**Prerequisite:** At least one bazel build based release process, governed by the `release-please` action must have already successfully been completed.

This includes, but is not limited to:
- docker container definitions of the build environments
- the versioning metadata (files `LAST_RELEASED_VERSION` and `NEXT_VERSION`)
- Makefiles
- The GitHub workflows relying on Makefiles and docker.
- When modifying the workflows, adapt the status badges for the builds in README.md

Wait for a successful release governed by the release-please action and based on a Bazel build. Then inspect the Docker build-environment definitions, LAST_RELEASED_VERSION, NEXT_VERSION, Makefiles, and GitHub workflows that rely on them. Remove artifacts from the old release process and update the README.md build status badges when workflows change.

Written by the indexing model from the issue text.