update IoT cloud demo (#876)

* update IoT APP store demo

* update IoT app store apps

* update IoT cloud demo document

* [Cloud demo] mount app store between two dockers

* [Cloud demo] update restart policy

* [Cloud demo] update help page

* [Cloud demo] update online demo address

test-tools/IoT-APP-Store-Demo/docker-compose.yml

@@ -0,0 +1,22 @@
+version: '2.0'
+
+services:
+  web_portal:
+    build: ./wasm_django
+    network_mode: "host"
+    depends_on:
+      - 'device_server'
+    restart: always
+    volumes:
+      - store:/app/static/upload/
+  device_server:
+    build:
+      context: ./wasm_django
+      dockerfile: ./server/Dockerfile
+    network_mode: "host"
+    restart: always
+    volumes:
+      - store:/app/static/upload/
+
+volumes:
+  store: