statefs-qt: don't install headers in include/qt5/ which is no longer imported by recipes depending on statefs-qt

qtaround, statefs-providers, statefs: updates the cmake flags to follow the new Qt install directories from the previous commit.

Set QT_DIR_NAME to an empty string so that Qt specific binaries are no longer installed in odd not-in-PATH places like /usr/bin/qt5/. It also removes the need for some ugly sed hacks. Cf: https://github.com/meta-qt5/meta-qt5/blob/master/classes/qmake5_paths.bbclass

Fixes incorrect dependencies to qtquick1 which built huge packages like qtwayland for no good reason...

This reverts commit 5027055e.

This reverts commit a8d98acc.

This reverts commit a407fec7.