Drop the KHTML framework as dependency (which was actually needed only to
disable javascript and friends from the KHTMLPart) and drop the KHTMLPart as
well, when previewing an HTML or XML file. Now we always use the second available
service offer, which is the katepart by default. The user can still render an
HTML entry, by opening it in the browser.
BUG: 201162
BUG: 353786
BUG: 354182
FIXED-IN: 15.12.0