[ui] refactor ui

gui/components/VPNMouseArea.qml

gui/components/VPNState.qml

gui/components/VPNToggle.qml

gui/components/VerticalSpacer.qml

gui/gui.qrc

gui/main.cpp

gui/main.qml

gui/providers/providers.json

gui/qml/BackgroundImage.qml

gui/qml/BridgesItem.qml

gui/qml/VPNSwitch.qml

gui/qml/VpnState.qml

gui/qml/main.qml

gui/qml/readme.txt

gui/resources/about.svg

gui/resources/arrow-left.svg

gui/resources/birds.svg

gui/resources/bridge.png

gui/resources/close.svg

gui/resources/donate.svg