[CMake] Move mentions of KF Archive dependencies over to the extractors

The purpose missed the somewhat recently added FictionBook2 and Krita
extractors. As the purpose can be ammended several times, just add
each extractor when it is added to the targets.

The CMake output will mention each dependent extractor:

* KF6Archive (required version >= 6.0.0), KDE Frameworks: ...
  Archive is needed for several extractors
  - Required for ODF extractor
  - Required for Office 2007 extractor
  - Required for FictionBook2 extractor
  - Required for Krita extractor