Refactor health check framework

[dovydas-an]

Clean up Python-based health check framework to alpha version (instrumentation for PyTest et al, support libraries, and container image).

[tilowiklundSensmetry]

@victor-linroth-sensmetry has created a new version of the runner (container) image. Most importantly it is now built around fsspec instead of cURL. This adds supports for protocols beyond HTTP. Worthy of special mention are data URIs that allow passing small scripts/requirements inline.

Currently in final review (internal merge request !8).

[victor-linroth-sensmetry]

Merge completed (internal merge request !8).

[victor-linroth-sensmetry]

Pushed updated image to Docker hub and updated helm charts for the cluster so it uses the new image.

[tilowiklundSensmetry]

Nothing new here, primarily awaiting an opportunity for useful feedback.