wip: costs reduction

[lemeurherve]

WIP, not for review, to be split, see #7073 for details

• feat(pipeline): allow to run on a limited plugin set #7077
• feat(pipeline): retrieve prep from archive if it exists #7079
• chore(pipeline): collect more info from test executions #7078
• chore(pipeline): cleanup before splits introduction #7085
• feat(pipeline): split test combinations #7086
• feat(pipeline): skip test combinations already passed in previous attempts #7087

Ref:

• Decrease BOM costs #7073
• Decrease BOM costs by splitting tests more efficiently jenkins-infra/helpdesk#5208

Testing done

CI

Example of a balanced split of a "full-test" on a limited set of plugins:

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests that demonstrate the feature works or the issue is fixed