Preflight checks for BTF support

[ovalenti]

Description

Add steps to the host heuristics to check the presence of some features required by the core_bpf collection method.

closes #1018

Checklist

• Investigated and inspected CI test results
• Updated documentation accordingly

Automated testing

• Added unit tests
• Added integration tests

Testing Performed

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[github-actions]

Kernel	Method	Without Collector Time (secs)	With Collector Time (secs)	Baseline median (secs)	Collector median (secs)	PValue
rhel.rhel-8	ebpf	230.457	237.76	204.92	213.7	🟢
ubuntu-os.ubuntu-1804-lts	ebpf	248.334	236.254	206.11	213.49	🟢
ubuntu-os.ubuntu-2004-lts	ebpf	247.161	242.615	236.1	234.97	🟢
ubuntu-os.ubuntu-2204-lts	ebpf	253.711	247.793	222.56	229.05	🟢

[erthalion]

Thanks, looks good. Couple of commentaries below, but also one request, would it be hard to add a few unit tests?

[erthalion]

In this case libbpf says feature detection may failed, makes sense to report errno?

[ovalenti]

I couldn't find a reference to the errno availability in the docs for that case. And the code suggests that it does not reflect the actual error reason.

[erthalion]

This one [1]? It seems this function does sys_bpf_fd and returns -errno if fd < 0.

[ovalenti]

errno is tested underneath, but when the error if reported at the API level, I am afraid this information is lost.

[erthalion]

Thanks, overall looks good.