Do not deploy unused QtQuick Controls styles

Often only one Qt Quick Controls 2 style is used in application, but other styles are included too increasing size of package (style plugins in APK). I don't find any ability to exclude unused styles from application package.

If style is statically declared at compile time e.g. by "import QtQuick.Controls.Material" that information can be used to deploy only this style.

If several styles used with runtime style selection qtquickcontrols2.conf could specify which styles should be deployed