Adapt KBibTeX docbooks to kf5

index.docbook
  remove entities already in kdoctools or obsolete/unused
  &kde; -> &kf5-full;
  remove appendix installation
man docbook
  "for KDE" -> "by KDE"
  remove options from kde3 and replace with reference to qt5options and kf5options
program.cpp
  "A BibTeX editor for KDE" -> "A BibTeX editor by KDE"
REVIEW:128320