LPS-44438 please read comments - Improving user-display tag

Hey Brian,

We have been improving the liferay-ui:user-display tag for staging but in a generic way.

The change has been reviewed by Chema, Nate, and myself. I've applied a commit I'm not sure about, I've changed the displayStyle="<%= 3 %>" attribute calls to displayStyle="3". I saw we are using both for <aui:col width for example I could found both occerences. I think the "3" is a bit nicer, but I'm not sure about your opinion. Also, if you think this is fine, I'll send a fixing pull for plugins as well.

Thanks,

Máté