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

plugins/wasm-rust/Makefile

@@ -0,0 +1,16 @@
+PLUGIN_NAME ?= say-hello
+REGISTRY ?= higress-registry.cn-hangzhou.cr.aliyuncs.com/plugins/
+BUILD_TIME := $(shell date "+%Y%m%d-%H%M%S")
+COMMIT_ID := $(shell git rev-parse --short HEAD 2>/dev/null)
+IMAGE_TAG = $(if $(strip $(PLUGIN_VERSION)),${PLUGIN_VERSION},${BUILD_TIME}-${COMMIT_ID})
+IMG ?= ${REGISTRY}${PLUGIN_NAME}:${IMAGE_TAG}
+
+.DEFAULT:
+build:
+	DOCKER_BUILDKIT=1 docker build \
+		--build-arg PLUGIN_NAME=${PLUGIN_NAME} \
+		-t ${IMG} \
+	    --output extensions/${PLUGIN_NAME} \
+	    .
+	@echo ""
+	@echo "output wasm file: extensions/${PLUGIN_NAME}/plugin.wasm"