Port the reCAPTCHA dialog to QML

CMakeLists.txt

resources/qml/Root.qml

resources/qml/dialogs/ReCaptchaDialog.qml

src/ReCaptcha.cpp

src/ReCaptcha.h

src/dialogs/ReCaptcha.cpp

src/dialogs/ReCaptcha.h

src/ui/UIA.cpp

src/ui/UIA.h