ubpf for unikraft
This is the initial merge of ubpf for unikraft as a proof of compile and run.
The unikraft part conists of a modified version of the test-netdev app to use the latest unikraft framework.
Especially uk_netdev_rx_one was adopted accordingly and the automatic buffer allocation alloc_rxpkts is configured as a callback.
The actual ebpf code is currently built-in as a hex array in bpf-binary.h
and is loaded and verified at the start in main, and executed for each incoming pkt
in the receive call uk_netdev_rx_one.
The maps integration and the corresponding relocation when loading the elf will follow shortly.