Add eBPF kernel headers workaround in k8s

[eh-am]

One our users in slack found out that if you don't have access to k8s nodes to install kernel headers, it's possible to build a docker images with these + pyroscope as a workaround.

It would be nice to document it so that other people also benefit from this info.

Source: https://pyroscope.slack.com/archives/C01FJRYENPQ/p1657750085227309?thread_ts=1657701092.332439&cid=C01FJRYENPQ