Create combined markdown report in weekly CI

[bernt-matthias]

I guess writing it to GITHUB_STEP_SUMMARY will still not work (because it's to large). But there is only one way to find out.

FOR CONTRIBUTOR:

• [ ] I have read the CONTRIBUTING.md document and this tool is appropriate for the tools-iuc repo.
• [ ] License permits unrestricted use (educational + commercial)
• [ ] This PR adds a new tool or tool collection
• [ ] This PR updates an existing tool or tool collection
• [ ] This PR does something else (explain below)