[bpf/nodefw] mvp/poc for a stateless fw (MystenLabs#15922)

## Description 
an mvp of an xdp based bpf firewall

## Test Plan 
local.  currently targeted to environments that can support xdp

`RUST_LOG=info cargo bpf run`

---
If your changes are not user-facing and do not break anything, you can
skip the following section. Otherwise, please briefly describe what has
changed under the Release Notes section.

### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

nre/bpf/nodefw/.cargo/config.toml

@@ -0,0 +1,2 @@
+[alias]
+bpf = "run --package xtask --"