Move storage.js, background.js and options in src directory

manifest.json

@@ -12,10 +12,10 @@
     "storage"
   ],
   "options_ui": {
-    "page": "options/options.html"
+    "page": "src/options/options.html"
   },
   "background": {
-    "scripts": ["storage.js", "background.js"]
+    "scripts": ["src/storage.js", "src/background.js"]
   },
   "browser_action": {
     "default_icon": "resources/icons/icon-24.png",

package.json

@@ -2,7 +2,7 @@
   "name": "shaarli-web-extension",
   "version": "0.0.1",
   "description": "Share your link to your Shaarli on Firefox Quantum",
-  "main": "background.js",
+  "main": "src/background.js",
   "keywords": [
     "web",
     "extension",