feat(controlstack): Add is_running property and wait_done method. Closes #133

Explanation of changes

feat(controlstack): Add is_running property and wait_done method

• controlstack.is_running returns if any of the ControlStack Components is running.
• controlstack.wait_done is a blocking method which unblocks if all ControlStack Components are done running or if they've timed out.

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Merge checklist

See also merge request guidelines

• Merge request has been reviewed and approved by a project maintainer.
• Merge request contains a clear description of the proposed changes and the issue it addresses.
• Merge request made onto appropriate branch (develop for most MRs).
• New code is fully tested.
• New code is documented and docstrings use numpydoc format.
• Changelog has been updated (when applicable).
• CI pipelines pass
  • black code-formatting passes (gitlab-ci),
  • test suite passes (gitlab-ci),
  • no degradation in code-coverage (codacy),
  • no (serious) new pylint code quality issues introduced (codacy),
  • documentation builds successfully (CI and readthedocs).