VE-533 / VE-534: re-style search results, add play button to videos in media item detail page

https://wikia-inc.atlassian.net/browse/VE-533
https://wikia-inc.atlassian.net/browse/VE-534

This commit also addresses two small bugs in `ve.ce.WikiaVideoNode.js` and `ve.ui.WikiaMediaInsertDialog.js`