erp5_officejs_appstore_website: Improve Landing page and set title in english

bt5/erp5_officejs_appstore_website/SkinTemplateItem/portal_skins/erp5_officejs_appstore_theme/data/all_apps.json.json

@@ -20,6 +20,11 @@
       "direct": {"className":"info"},
       "attributes": {"data-info":"records"}
     }]
+  }, {
+    "type": "p",
+    "direct": {"className": "translate ui-content-element responsive"},
+    "attributes": {"data-i18n":"pages.home.info_officejs"},
+    "logic": {"text": "OfficeJS is the only appstore compatible with Windows, MacOS, Android, Firefox OS, Linux, XiaomiOS, Bada, Tizen etc. Start browsing and using available applications. No login required."}
   }, {
     "generate":"widget",
     "type": "listview",

bt5/erp5_officejs_appstore_website/SkinTemplateItem/portal_skins/erp5_officejs_appstore_theme/lang/en-EN/dict.json.json

@@ -2,7 +2,7 @@
   "global": {
     "home": "Home",
     "search_apps": "Search Apps",
-    "default_page_title": "",
+    "default_page_title": "OfficeJS Appstore",
     "menu": "Menu",
     "pagination": {
       "first": "First",