[ENH] featured links: auto-resize the iframe height with javascript to match the content height and avoid vertical scrollbars (when using a relative link, i.e. on the same site) + changed default height from 600 to 700px + remove iframe border (to better fake a tiki content).

It is only done if the url does not start with a protocol (e.g. http://, https://, ...) because web browsers generate a security alert when trying to do this with an iframe content that is not on the website (same domain name) of the page that includes the iframe.