Use a template for helm chart version bumps with updatecli instead of multiplying manifests

[lemeurherve]

What feature do you want to see added?

I'd like to use a template to define helm chart bump updatecli manifests instead of duplicating existing manifests when we're adding a service.

Advantages:

• Align all helm chart bump manifests to avoid errors and oversights
• Simplify code, less files
• Easier to check a single source of trust than to check every manifest

Upstream changes

No response

[lemeurherve]

PR for later:

• https://github.com/jenkins-infra/kubernetes-management/pull/5419