removed default information from plugin.json files; move plugin descriptions...

removed default information from plugin.json files; move plugin descriptions to language files, where available

plugins/ZenMode/lang/en.json

 {
     "ZenMode": {
+        "PluginDescription": "Stay Zen with Piwik. Zen mode keeps things simple. It is available via the icon in the top right of the screen.",
         "SearchForAnything": "Search for anything",
         "QuickAccessTitle": "Search for menu entries, reports and websites",
         "HowToSearch": "To search for menu items, reports or websites use the search box on the top right or press 'alt+f'.",

plugins/ZenMode/plugin.json

-{
- "name": "ZenMode",
- "version": "0.1",
- "description": "Stay Zen with Piwik. Zen mode keeps things simple. It is available via the icon in the top right of the screen.",
- "theme": false
-}
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