add devcontainer for wasm-go plugin developing (#749)

Co-authored-by: Xunzhuo <bitliu@tencent.com>

plugins/wasm-go/.devcontainer/gen_config.py

@@ -0,0 +1,76 @@
+import json
+import sys
+
+
+plugin_name = sys.argv[1]
+
+with open("extensions/"+plugin_name+"/config.json", "r") as f:
+    plugin_config = json.load(f)
+
+config = f'''static_resources:
+  listeners:
+  - address:
+      socket_address:
+        address: 0.0.0.0
+        port_value: 8080
+    filter_chains:
+    - filters:
+      - name: envoy.filters.network.http_connection_manager
+        typed_config:
+          '@type': type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
+          codec_type: AUTO
+          stat_prefix: ingress_http
+          route_config:
+            name: test
+            virtual_hosts:
+            - name: direct_response_service
+              domains: 
+              - "*"
+              routes:
+              - match:
+                  prefix: "/"
+                direct_response:
+                  status: 200
+                  body:
+                    inline_string: "hello world\\n"
+              # - match:
+              #     prefix: "/"
+              #   route:
+              #     cluster: service-backend
+          http_filters:
+          - name: {plugin_name}
+            typed_config:
+              "@type": type.googleapis.com/udpa.type.v1.TypedStruct
+              type_url: type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm
+              value:
+                config:
+                  name: wasmdemo
+                  vm_config:
+                    runtime: envoy.wasm.runtime.v8
+                    code:
+                      local:
+                        filename: ./extensions/{plugin_name}/main.wasm
+                  configuration:
+                    "@type": "type.googleapis.com/google.protobuf.StringValue"
+                    value: '{json.dumps(plugin_config)}'
+          - name: envoy.filters.http.router
+            typed_config:
+              '@type': type.googleapis.com/envoy.extensions.filters.http.router.v3.Router
+  # clusters:
+  # - name: service-backend
+  #   connect_timeout: 600s
+  #   type: STATIC
+  #   lb_policy: ROUND_ROBIN
+  #   load_assignment:
+  #     cluster_name: service-backend
+  #     endpoints:
+  #       - lb_endpoints:
+  #           - endpoint:
+  #               address:
+  #                 socket_address:
+  #                   address: 127.0.0.1
+  #                   port_value: 8000
+'''
+
+with open("extensions/"+plugin_name+"/config.yaml", "w") as f:
+    f.write(config)