JBIDE-17849 CSS Hyperlinks aren't working on non-WTP projects

An utility helper method is added due to find pages in projects that are not the WTP ones
(has no web-roots that can be achieved by WTP methods)

Signed-off-by: vrubezhny <vrubezhny@exadel.com>
BTW, the method org.jboss.tools.common.web.WebUtils.getWebRootFolders(IProject, boolean) doesn't return WebRoots for a Static Web Projects (it returns an empty array) - is it a bug?