Use Base images in RPM packaging pipelines

This MR implements base image optimization for RPM packaging pipelines, utilizing pre-built base images from the GCP registry to improve build efficiency and consistency.

Description

This MR modifies RPM packaging pipelines (Rocky Linux and Fedora) to use pre-built base images from the Tezos GCP registry, eliminating the need to build dependencies from scratch.

Key Changes:

• Uses the images/base-images/Dockerfile.rpm base images
• Updates RPM repository pipeline jobs to reference pre-built base images via ${GCP_REGISTRY}/$CI_PROJECT_NAMESPACE/tezos/$FLAVOUR-$DISTRIBUTION-$RELEASE
• Applies to both Rocky Linux and Fedora packaging workflows

Context & Relationship:

• **Conceptually Similar to MR !18947 (merged) **: Both implement strategic base image usage for packaging optimization
• **Associated to MR !19198 (merged) **: Builds upon the established GCP registry infrastructure and base image framework

Benefits:

• Unifies base image approach across all packaging workflows (Debian, Ubuntu, Fedora, Rocky Linux)
• Standardized base images reduce build variability and potential failures
• Built-in Datadog integration for better pipeline monitoring

Testing

check if the base image is used https://gitlab.com/tezos/tezos/-/jobs/11333898851

Normal   Pulled   Successfully pulled image "us-central1-docker.pkg.dev/nl-gitlab-runner/protected-registry/tezos/tezos/rockylinux:9.3" in 5.847s (5.847s including waiting). Image size: 168034635 bytes.

$ . ./scripts/ci/datadog_send_job_info.sh
Sending job-level info to Datadog
Tags sent

You can run a pipeline from the gitlab interface, or look at this one https://gitlab.com/tezos/tezos/-/pipelines/2036132511 or this one https://gitlab.com/tezos/tezos/-/pipelines/2036126143

Scheduled pipeline : https://gitlab.com/tezos/tezos/-/pipelines/2036133457