ruby: eBPF profiling

For Ruby we currently use rbspy. Ruby is a fairly simple VM, like Python, so an eBPF profiler would be about the same project size as our [PyPerf](https://github.com/Granulate/bcc/tree/master/examples/cpp/pyperf) - a profiler driver which loads a set of perf_events BPF programs that profile all Ruby processes running on the system.

I doin't think we should use BCC like PyPerf - instead, a driver written in C/C++/Rust & BPF programs written in C over libbpf is the way to go.

Existing resources:
* [rbperf](https://github.com/facebookarchive/rbperf) - haven't tried it but it's a functioning Ruby profiler for a single PID and a single Ruby version. BPF is written in C, driver is written in Python (BCC). Seems unmaintained. We can draw inspiration from it.