Online validation suite reports

[gipert]

Ideas:

• implement the validation report as markdown files in a dedicated subdirectory below docs/validation
• the plots/text generated by the validation suite are referenced by these static pages
• in the CI, after the validation suite has run, the missing plots/text are available -> we can build this additional part of the documentation with the same machinery as the other docs, only for the main branch
• on ReadTheDocs and locally, docs/validation pages are not built. Locally, the user can generate them manually with some command (e.g. make docs-validation
• the CI pushes the built HTML pages to the gh-pages (we can use https://github.com/actions/deploy-pages)
• GitHub does the rest, i.e. making these pages available at https://legend-exp.github.io/remage
• we link this website in the main remage doc pages
• different versions of the webpages can be stored in subdirectories on the gh-pages branch, this would allow us to keep online validation suite reports for e.g. each tagged version and the main branch
• to look at the validation report in PRs, we need to think about a solution. A simple one is to include the html pages as an artifact that the submitter has to download and inspect. We can also convert them to PDF and make this available instead.

[tdixon97]

i also put some ideas in #162

[tdixon97]

I like these ideas but idk how it will work technically. Is an alternative to hist on github pages?
As well as the technical parts for uploading on the docs we have some small issues.

• need to save geant4 vis as PNG, JPEG etc. (didn't work when I tried)
• could try VTK to have interactive graphics in HTML ?

[gipert]

We can also easily convert from PDF to bitmap ourselves. In principle we can have JavaScript stuff running on GitHub pages, it seems. So anything based on it should work. I'm not an expert on this stuff tho

[tdixon97]

I dont though about it, but I quite like the idea of embedding interactive plots (Eg. consider the current validation plots with point clouds are pretty much useless), but maybe lets set up something static first?

[gipert]

Yes let's have something static first, adding interactive things might be not so hard then.