Add 'get_variable_from_yaml' option into Workflow.groovy

Add possibility to set a job parameter, taking the value from
the specified key in the remotely stored YAML, for example:

    TARGET_CLUSTER:
      type: StringParameterValue
      get_variable_from_yaml:
          yaml_url: SI_CONFIG_ARTIFACT
          yaml_key: .clusters[0].CLUSTER_NAME

, where SI_CONFIG_ARTIFACT - a parameter or artifact which contains
an URL to the YAML file; and '.clusters[0].CLUSTER_NAME' is the path
to the required key in this YAML file

Task:       PRODX-19061
Related to: PRODX-16926

Change-Id: Idd246ee8df44e8becfd9f101095917efa4a44820
1 file changed