drop down control to change 'navigate by' search element
small navigation popup relationally linked to drop down control
dynamic tool tips added to previous and next 'navigate by' toolbar
controls

Change-Id: I4b1215b74b488f2571b529d9946f6574de6e270a
Reviewed-on: https://gerrit.libreoffice.org/40776Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>