Allow setting the package name directly from CMake properties.
If the package name is not set manually under AndroidManifest.xml
nor build.gradle, then the value set by this property is used.
The value is passed to build.gradle as "namespace" which is the
way to set the package name after AGP 7.4 instead of
AndroidManifest.xml "package" attribute.
Task-number: QTBUG-106907
Change-Id: I94bd73c294d751eabfd96c0a10a6b3ff270d8137
Reviewed-by: Tinja Paavoseppä <tinja.paavoseppa@qt.io>