Added homepage, description & keywords (#6969)

Added homepage, description & keywords

package.json

@@ -1,5 +1,7 @@
 {
   "name": "@storybook/root",
+  "description": "Storybook is an open source tool for developing UI components in isolation for React, Vue and Angular. It makes building stunning UIs organized and efficient.",
+  "homepage": "https://storybook.js.org/",
   "version": "5.1.0-rc.0",
   "private": true,
   "repository": {
@@ -245,5 +247,27 @@
         "Other"
       ]
     ]
-  }
+  },
+  "keywords": [
+    "ui",
+    "user interface",
+    "components",
+    "storybook",
+    "storybookjs",
+    "react",
+    "reactjs",
+    "angular",
+    "angularjs",
+    "vue",
+    "vuejs",
+    "babel",
+    "eslint",
+    "frontend",
+    "jamstack",
+    "documentation",
+    "tool",
+    "templated",
+    "reuseable",
+    "markup"
+  ]
 }