feature: parse 'schedule' job log for dependency cycles

[jeremyd2019]

could look for the most recent 'schedule' job, parse its log, and build a UI to build the optional_deps string.

[lazka]

I could also write it into the status.json: https://github.com/msys2/msys2-autobuild/releases/tag/status

[lazka]

The basic list of cycles is now included in https://github.com/msys2/msys2-autobuild/releases/tag/status

[jeremyd2019]

https://github.com/msys2-arm/msys2-autobuild-controller/blob/main/job_log_parse.py could probably be removed in that case (I don't think it is called anywhere yet), and instead add code to load the status json. That would also be useful for #9