feat(wireguard-broker): merge from dev/broker-architecture, fixes, test

* wireguard-broker: merge from dev/broker-architecture
* use zerocopy instead of lenses
* Require use_broker feature flag to comile broker binaries
* Remove PhantomData from BrokerServer & BrokerClient
* Modify mio client rx to be non-recursive, add integration test

Co-authored-by: Karolin Varner <karo@cupdev.net>
Co-authored-by: Prabhpreet Dua <615318+prabhpreet@users.noreply.github.com>

wireguard-broker/src/lib.rs

@@ -0,0 +1,19 @@
+#[cfg(feature = "enable_broker")]
+use std::result::Result;
+
+#[cfg(feature = "enable_broker")]
+pub trait WireGuardBroker {
+    type Error;
+
+    fn set_psk(
+        &mut self,
+        interface: &str,
+        peer_id: [u8; 32],
+        psk: [u8; 32],
+    ) -> Result<(), Self::Error>;
+}
+
+#[cfg(feature = "enable_broker")]
+pub mod api;
+#[cfg(feature = "enable_broker")]
+pub mod netlink;