fdo#72947 Startcenter: display more userfriendly file urls in tooltips

Use INetURLObject to get a readable url (it displayes special characters
too).Handle file urls and non-file urls on a different way (Thanks
to Stephen Bergmann for the idea).

(cherry picked from commit 31dfeee42e9b08ed7031b6c50d0c674122d5245c)

Conflicts:
	sfx2/source/control/recentdocsviewitem.cxx

Change-Id: I4aab5e2546ae70e5a3d85b12e26e021bfa244999
Reviewed-on: https://gerrit.libreoffice.org/7370
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>
Reviewed-by: Andras Timar <andras.timar@collabora.com>