Improve Development Docker Image Build Workflow

[popescu-v]

Description

Currently, the khiopspydev-* Docker images are pushed to the GitHub container registry, each time with the latest tag, thus overriding previous Docker images. This hinders development of concomitant feature branches, where the updated Docker images (overridden for a specific feature branch) is accidentally used for launching the testing and packaging GitHub CI workflows. The goal of this issue is to streamline the Docker image building process, so that this dev chore disappears.

Questions/Ideas

• The test job can be removed: indeed, the Khiops binaries are now installed from upstream Khiops-generated sources (native OS-specific package, or Conda package) and are thus tested upstream.
• Versioning can be added to the Docker images, thus: major.minor.patch.increment, where major, minor and patch are from the khiops GitHub repository, and increment is zero-versioning-based, but orthogonal to the versioning scheme of khiops-python itself;
• Docker images tagged with specific versions can thus be pushed;
• Docker images are only pushed on manual workflow_dispatch events, when explicitly instructed to do so;
• Docker images are also tagged latest (and their tags pushed thereof) only if the workflow is manually launched from the dev or main branch (as these images are not "feature-branch" images anymore). Tag overriding is thus possible for the latest tag.
• The unit-tests, pip and conda workflows (which use the development Docker images) use the latest tag by default for these images, but allow for explicit overriding by manual launch via the workflow_dispatch events.

[popescu-v]

This seems high-priority, because without it, any modification of the Docker images that is done on a feature branch can hinder development of other feature branches if these modified images are pushed to the GitHub registry.