Fix entities with wrong links

* replace link in install-compile.docbook to page with kde4 specific instructions with link to main page of techbase
* install-intro.docbook
  remove usage of entity &package; kde does only release single application tarballs (with a few exceptions like calligra, kdepim, kdewebdev)
  &kde-ftp; and &FTP; are gone you can get source tarballs afaik only via download.kde.org
* Add note that install-compile.docbook install-intro.docbook  are deprecated and should be removed in Frameworks 6
REVIEW:123850