CMake Build doesn't detect Prometheus

[Richard Russo]

I've noticed that the CMake build doesn't seem to detect Prometheus libraries, although configure can.

It seems like a script to find it would be needed based on the output from the CMake github automation: https://github.com/coturn/coturn/actions/runs/6622872744/job/17989011141#step:5:106

There's some other libraries listed that also can't be found. I'm not sure if the CMake build path is a work in progress or intended to be used as the main build?

Thanks,

Richard