community/bcc: devendor libbpf (and update main/linux-headers to 5.10.27)

bcc can be compiled without the bpf submodule if explicitely requested.

The submodule provided libbpf (added as dependency) as well as required kernel headers, which are more problematic: add a patch to fix compilation on our kernel.
^ this also required pulling up linux-headers from 5.7 to 5.10 (current lts version), should I open a separate MR for this or is it OK to leave it here? (I now see there also are patches sent by mail, which is just as good for me to be honest -- is there a preferred way of contributing? if it's the same to everyone I'll send further patches by mail once current MRs have been merged)

cc @acj