Monitoring for lost samples in kernel space and failed packetparser reports for ring buffers

**Is your feature request related to a problem? Please describe.**

With perf buffers, we can monitor for lost samples via https://github.com/cilium/ebpf/blob/e4d11b5080301912e47c99b84bb522681d600b62/perf/reader.go#L49.

Even then, there's no reporting from the eBPF program when writing to the buffer fails.

**Describe the solution you'd like**

Metrics for lost events should reflect both fails to write to the ring buffer/perf buffer as well as lost reports from userspace.

**Additional context**

It is difficult to tune the ring buffer size and sampling rate without knowing if any reports are being dropped.