Strip html tags from category and product meta descriptions.

So we can avoid raw tags displayed in search results on google, bing etc..

```HTML
        <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
        <meta name="created" content="3rd Gen 2014 10:47" />
        <meta name="description" content="
    &lt;p&gt;BUSTA A SACCO AVANA CON SOFFIETTI LATERALI 4CM + FONDO AD INVITO. ADESIVO STRIP.&lt;/p&gt;
" />
        
    <link rel="shortcut icon" href="/static/favicon.ico" />
```