Support workflow parameters in workflow metadata

[kulinskyvs]

Summary

Motivated by #5885, could it be possible to add support of workflow parameters for workflowMetadata on the workflow template level?

Use case

I have a reusable workflow with some workflowMetadata defined - I would like to refer to workflow input parameters from workflowMetadata section (use these values when building the labels for example).

apiVersion: argoproj.io/v1alpha1
kind: WorkflowTemplate
metadata:
  name: my-workflow-template
spec:
  arguments:
    parameters:
      - name: env
        value: "prod"
      - name: platform
         value: my-platform
  workflowMetadata:
    labels:
      enviroment: "{{ workflow.parameters.env }}"
      platform: "{{ workflow.parameters.platform }}"
  templates:
  .........

Supporting workflow parameters inside the workflowMetadata section (labels, for example) can increase its reusability and makes the workflows submitted from this template more consistent and discoverable (labeling is done regardless of the labels provided when submitting the workflow through UI or argocli).

[alexec]

This be raised an an enhancement proposal.