Support loading custom bpf programs through the jsonc configuration

[maryamtahhan]

Enable a user to load their own bpf program on the interface being used for AF_XDP.

Note: this is partially enabled through the bpf map pinning support. Perhaps Also document this better to allow the end user to use whatever their preferred BPF loader is.

[maryamtahhan]

This is enabled through the pinned map support that's been merged to CNDP. Demonstrated in the cndp-frr demo. As such I will mark this feature as closed