Add stage to import image and automatically import if possible

[michaelsauter]

• New stage odsComponentStageImportOpenShiftImage.
• New "special" stage odsComponentStageImportOpenShiftImageOrElse
  which either imports an image or executes the given closure.
• Images are now tagged with the short Git SHA, dropping the Jenkins
  build number prefix.

Example usage:

@Library('ods-jenkins-shared-library@3.x') _

odsComponentPipeline(
  imageStreamTag: 'ods/jenkins-agent-golang:3.x',
  branchToEnvironmentMapping: [
    'develop': 'dev',
    'release/*': 'test',
    'master': 'prod'
  ]
) { context ->
  odsComponentStageImportOpenShiftImageOrElse(context) {
    stage('Build') {
      // custom stage
    }
    odsComponentStageScanWithSonar(context)
    odsComponentStageBuildOpenShiftImage(context)
  }
  odsComponentStageRolloutOpenShiftDeployment(context)
}

This allows users exactly which steps to skip when an image can be imported. Further, it allows to use the "import image stage" as a standalone feature as well.

[clemensutschig]

this is amazing @michaelsauter

One small comment though - I am wondering if this would not break MRO - if MRO expects to build an image - and in reality it's not built ... or deployed, or ....

[henrjk]

Awesome addition!

I don't have time to look into reviewing this in depth.

However I did not see any issues on a cursory review.

[michaelsauter]

@clemensutschig I thought about this, and decided that as a first step, we just disable the functionality when in an orchestration context (see https://github.com/opendevstack/ods-jenkins-shared-library/pull/400/files#diff-c50f3cdbc0d4a66242907069707b7463R17-R23). Maybe this is even a long-term solution, as the orchestration pipeline has its own logic to bypass building a component altogether.

[gerardcl]

great!!!
also loving the push for ff merge!