Add support for opentelemetry tracing

[bobrik]

Example trace:

To produce it:

1. Run jaeger:

docker run --rm -it --net host jaegertracing/all-in-one:1.50

2. Run ebpf_exporter:

make && make -C examples && sudo ./ebpf_exporter --config.dir=examples --config.names=biotrace --otlp.addr=localhost:4317

3. Open jaeger ui on port 16686.

[bobrik]

Current status: retransmits in kernel space are visible on traces that start in userspace.