bpf fs is not mounted on a clean Linux box

[Jiang1155]

When bpf fs is not mounted, you will see the following errors:

go run server.go primary
2023-10-05T13:37:09.204-0400 INFO Starting server in primary mode
2023-10-05T13:37:09.205-0400 ERROR failed to create eBPF collection: %!w(*fmt.wrapError=&{map tcp_balancing_targets: pin map to /sys/fs/bpf/tc/globals/tcp_balancing_targe
ts: no such file or directory 0xc0000b4960})
2023-10-05T13:37:09.205-0400 INFO Started listening in 127.0.0.1:8080 successfully !
2023-10-05T13:37:09.205-0400 INFO Updating with k=0 v=3
2023-10-05T13:37:09.205-0400 ERROR Unable to load map at /sys/fs/bpf/tc/globals/tcp_balancing_targets : %!w(sys.wrappedErrno={2})
^Csignal: interrupt

To fix that, you can mount bpf fs manually by the following cmds:

mkdir /sys/fs/bpf
mount -t bpf none /sys/fs/bpf
mkdir -p /sys/fs/bpf/tc/globals/

It will be good to put this info in readme. thanks