Improve service worker (#1353)

* Improve service worker

 - Add new env variable in WebPack "NODE_ENV"
 - Add new service worker for mode dev that permit to by pass response in cache storage
 - Add new WorkAdventure icon

* Remove console.log

* Add service worker file prod and dev

front/dist/service-worker-dev.js

@@ -0,0 +1,39 @@
+let CACHE_NAME = 'workavdenture-cache-v1';
+let urlsToCache = [
+    '/'
+];
+
+self.addEventListener('install', function(event) {
+    // Perform install steps
+    event.waitUntil(
+        caches.open(CACHE_NAME)
+            .then((cache) => {
+                return cache.addAll(urlsToCache);
+            })
+    );
+});
+
+self.addEventListener('fetch', (event) => {
+    event.respondWith(
+        caches.match(event.request)
+            .then((response) => {
+                return fetch(event.request).then((response) => {
+                        //Dev service worker, just return reponse
+                        return response;
+                    }
+                );
+            })
+    );
+});
+
+self.addEventListener('wait', function(event) {
+    //TODO wait
+});
+
+self.addEventListener('update', function(event) {
+    //TODO update
+});
+
+self.addEventListener('beforeinstallprompt', (e) => {
+    //TODO change prompt
+});