Custom validators - Workflow execution order

[Erikhu1]

For Trudag tool to be able to access artifacts from other workflows, run Trudag after all other workflows have finished.

• Add parent workflow to contain and trigger all non-trudag workflows, on pull request.
• Child workflows create "completion flags" (artifacts).
• Parent workflow waits for and gathers all completion flags.
• Trudag triggered when parent workflow completed.

[github-actions]

The created documentation from the pull request is available at: docu-html