v1.8.0 - container-image supports tag-driven CLI image pattern

Adds tag_pipeline boolean input to the container-image template.
When true, the build job also fires on $CI_COMMIT_TAG and tags the
image with the version (alongside :latest). Passes VERSION into the
Containerfile via --build-arg so multi-stage builds can stamp it
into the binary's ldflags.

CLI consumers (bairn, future Go/Rust binaries) consume this with
tag_pipeline: true; their existing latest-on-Containerfile-change
behavior is unchanged. Catalog's own ci/ci-go/ci-rust images use
the default tag_pipeline: false and behave exactly as in v1.7.0.

Backwards-compatible.