contrib: add qml in .gitignore
Fixes the following untracked files:
? contrib/qml/QML/plugins.qmltypes ? contrib/qml/QML/qmldir ? contrib/qml/QtCore/libqtqmlcoreplugin.a ? contrib/qml/QtCore/libqtqmlcoreplugin.prl ? contrib/qml/QtCore/plugins.qmltypes ? contrib/qml/QtCore/qmldir ? contrib/qml/QtQml/Models/libmodelsplugin.a ? contrib/qml/QtQml/Models/libmodelsplugin.prl ? contrib/qml/QtQml/Models/plugins.qmltypes ? contrib/qml/QtQml/Models/qmldir ? contrib/qml/QtQml/WorkerScript/libworkerscriptplugin.a ? contrib/qml/QtQml/WorkerScript/libworkerscriptplugin.prl ? contrib/qml/QtQml/WorkerScript/plugins.qmltypes ? contrib/qml/QtQml/WorkerScript/qmldir ? contrib/qml/QtQml/libqmlplugin.a ? contrib/qml/QtQml/libqmlplugin.prl ? contrib/qml/QtQml/plugins.qmltypes ? contrib/qml/QtQml/qmldir ? contrib/qml/QtQuick/tooling/Component.qml ? contrib/qml/QtQuick/tooling/Enum.qml ? contrib/qml/QtQuick/tooling/Member.qml ? contrib/qml/QtQuick/tooling/Method.qml ? contrib/qml/QtQuick/tooling/Module.qml ? contrib/qml/QtQuick/tooling/Parameter.qml ? contrib/qml/QtQuick/tooling/Property.qml ? contrib/qml/QtQuick/tooling/Signal.qml ? contrib/qml/QtQuick/tooling/libquicktoolingplugin.a ? contrib/qml/QtQuick/tooling/libquicktoolingplugin.prl ? contrib/qml/QtQuick/tooling/qmldir ? contrib/qml/QtQuick/tooling/quicktooling.qmltypes ? contrib/qml/builtins.qmltypes ? contrib/qml/jsroot.qmltypes
