first pass at removing the sidebar widget

This attempts to remove references from the sidebar widget plugin, that attempts to directly access/manipulate the database.

We suggest this functionality get moved into a seperate "add-on" plugin that is wrapped in the following to make sure the main plugin is loaded/activated

```php

if (class_exists('Kaltura_AllInOneVideoPackPlugin')) {

    // Load up sidebar widget plugin

}
```

This way we won't have to maintain a seperate WordPress VIP branch and the sidebar widget would be optional with a note about why.