Temporarily use MouseArea for links in Pdf(Multi)PageView

HoverHandler.cursorShape is new API in 5.15, so we have to use
MouseArea for 5.14.

This patch can be reverted as soon as 5.14 is no longer supported.

Change-Id: I1c830215729038095ec33ece36a1a83108cbd835
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>