use docs hosting site to host html reports

[flynneva]

would be nice to auto-generate some documents, add them to a github pages site and have a page / folder for people to add their auto-generated .html reports.

• [x] choose a docs generation approach for the code (doxygen most likely candidate)
• [x] update comments in code to match docs framework requirements
• [x] generate some docs
• [x] host it on github pages
• [x] add version selector to docs so that we can track results over time / versions of executors
• [ ] add instructions on how to contribute results if desired
• [x] upload .html .md reports as individual pages on docs site
  • [ ] add sub-folders for different platforms

[flynneva]

this also would allow closed-source contributors to share their results for others to see in one central location

[flynneva]

For others reference, there now exists the ros2_realtime_benchmarks repo that will host more than just the reference_system reports.

I think adding a link to this site within the docs of this repo will be sufficient to complete this issue.

[flynneva]

Slight change to this: we should adjust the reporting scripts to generate markdown files with html embedded in them as the figures, similar to what performance_report does