POC - AF_XDP device plugin and CNI - BPFd integration

[maryamtahhan]

1. Investigate the possibility of replacing the BPF calls to load/unload BPF programs on/off interfaces in the AF_XDP K8s Plugins with BPFd.
2. POC + Document the integration.

• Ramp up on BPFd.
• Install BPFd in a kind cluster.
• Wrap up the AF_XDP BPF prog in a container image.
• Integrate the AF_XDP device plugin with BPFd - In progress
• Integrate the AF_XDP CNI with BPFd - In progress
• Allow custom BPF/AF_XDP program installation on the netdev
• Test the integration.
• Document the integration.

** Note 1**

Aya doesn't currently support XSK maps:

[2023-08-14T12:42:53Z WARN  aya::bpf] The map xsks_map is of type BPF_MAP_TYPE_XSKMAP which is currently unsupported in Aya, use `allow_unsupported_maps()` to load it anyways
[2023-08-14T12:42:53Z WARN  bpfd::rpc] BPFD load error: BpfLoadError(
        UnsupportedMap,
    )

As such integration work will be completed with an example BPF program that will need to be updated later in time.

** Note 2**

bpfd migrated from bpfd.dev to bpfd.io. This change will need to be added to the AF_XDP device plugin when the next version of bpfd is released.

[maryamtahhan]

After discussion with the bpfd team - the AF_XDP DP will let bpfd do everything from a map management POV for the AF_XDP netdev. So, the AF_XDP DP will need to retrieve the map information and extend the Pod spec with the right volume information. This requires a few small updates to the DP which are currently in progress.