Add on-cluster workflow test to CI

[elliotgunton]

Pull Request Checklist

• Fixes Integrate Argo Workflows into Hera's CI #652
• Tests added
• Documentation/examples added
• Good commit messages and/or PR title

Description of PR
Introduce local Argo cluster workflow tests to CI, and make targets to set up a local cluster for testing (this worked very well on GitHub codespaces, where I could even get a web UI to the cluster).

Added a single test to confirm the workflow runs via create and reaches the succeeded status.phase. We can think about creating a more flexible/extensible framework for adding on_cluster tests -

• I'd like to use a subset of our examples
• But we want to assert on more than the status.phase, e.g. output values, running order, skipped nodes etc, which would require bespoke tests for each
• It would also be good to have a wrapper for fetching these values, e.g. getting a node requires iterating through the status.nodes dictionary, which is keyed by hashes, so you have to check displayName from the values.

[flaviuvadan]

This looks really great as a first version!

Also def open to k3d as Sam mentioned

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (19fa389) 79.7% compared to head (5a61b08) 79.7%.

Additional details and impacted files

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  Coverage   79.7%   79.7%           
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  Files         45      45           
  Lines       3722    3722           
  Branches     754     754           
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  Hits        2970    2970           
  Misses       558     558           
  Partials     194     194           

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[flaviuvadan]

This LGTM! The next iteration can address some of the other concerns you mentioned in the description. Thx again for adding this <3