Move kwallet-query docbook to correct subdir

move docbook into subdit with matching name in l10n subdir + adapt docs/CMakeLists.txt

Rationale:

The Translated docbooks in this frameworks are missing in the tarball, see https://todo.kde.org/?controller=task&action=show&task_id=520

To find out which subdir of docs/frameworks subdir it should grab translated
docs from, the frameworks release script uses the name of the subdir in the sources.

On the other hand the script autogen.sh in l10n-kf5/scripts generates the CMakeLists.txt files
with the correct install paths/names for the language docbooks using the dirnames in l10n/[lang]/documentation.
REVIEW:128638