Add initial XDP skeleton (#1052)

* These flags are arch specific

* Add eBPF program

This commit adds the eBPF program used to determine if packets should be routed to quilkin's AF_XDP sockets

* Add first pass of an interface to abstract quilkin's interface to XDP sockets

* Not used yet, don't impact compile times

* .

.cargo/config.toml

@@ -1,4 +1,4 @@
-[target.'cfg(all())']
+[target.'cfg(target_arch = "x86_64")']
 rustflags = [
     "-Ctarget-feature=+aes,+avx2",
 ]

.gitignore

@@ -35,6 +35,7 @@ quilkin-*.zip
 # Generated by Cargo
 # will have compiled files and executables
 /target/
+crates/ebpf/target/
 
 # These are backup files generated by rustfmt
 **/*.rs.bk