Reduce duplication using a single Dockerfile

[ferrarimarco]

Proposed Changes

1. Reduce code duplication by using a single Dockerfile for both the standard and slim flavors of the super-linter image. To stop at the right point, we use target build stages.
2. Don't check if the versions file exist before building it. Setting the WRITE_LINTER_VERSIONS_FILE to true would suffice. This is necessary because we build the versions file twice (slim image, standard image) because we add more linters in the standard image, and need to rebuild the file to include those additional linters.
3. Fix setting BUILD_DATE in all the workflows. It was empty before this fix.

PS: I know that there's a lot of duplication in GitHub Actions workflow definitions, but it's a job for another day.

Readiness Checklist

Author/Contributor

• If documentation is needed for this change, has that been included in this pull request

Reviewing Maintainer

• Label as breaking if this is a large fundamental change
• Label as either automation, bug, documentation, enhancement, infrastructure, or performance

Requisites

• Uninstall Dockerfilelint #2195

[admiralAwkbar]

@ferrarimarco This is amazing