Extract rust snippets and reference them

snippets/rust/src/send_payment.rs

@@ -0,0 +1,11 @@
+use std::sync::Arc;
+
+use anyhow::Result;
+use breez_sdk_core::*;
+
+async fn send_payment(sdk: Arc<BreezServices>) -> Result<()> {
+    let bolt11 = "...";
+    sdk.send_payment(bolt11.into(), None).await?;
+
+    Ok(())
+}