feat: add wasm-rust sdk with say-hello simple extension (#350)

plugins/wasm-rust/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "higress-wasm-rust"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+proxy-wasm = "0.2.1"
+serde = "1.0"
+serde_json = "1.0"
+uuid = { version = "1.3.3", features = ["v4"] }