Health Check (Python) alignment

[operdeck]

Is your feature request related to a problem?

Completely align Python version of health check with the R version - except where there are improvements already (e.g. tree map of missing values)

Describe the solution you'd like

All numbers and text aligned with R version, robust against all versions of the DM we have, use nice Quarto features where applicable (like in the offline model reports). Rework plotting code to the pdstools library where appropriate.

Describe alternatives you've considered

Additional context

[StijnKas]

At this point I think the Python health check is more feature-complete than the R version, so closing this (fyi @operdeck)