welcomeview: implement new design

CMakeLists.txt

qml.qrc

resources/icons/keyboard_black_24dp.svg

src/app/MainApplicationWindow.qml

src/app/appsettingsmanager.h

src/app/commoncomponents/EditableLineEdit.qml

src/app/commoncomponents/MaterialButton.qml

src/app/commoncomponents/PhotoboothView.qml

src/app/commoncomponents/TextMessageDelegate.qml

src/app/constant/JamiStrings.qml

src/app/constant/JamiTheme.qml

src/app/mainapplication.cpp

src/app/mainview/components/JamiIdentifier.qml

src/app/mainview/components/TipBox.qml

src/app/mainview/components/WelcomePage.qml

src/app/qmlregister.cpp

src/app/tipsmodel.cpp

src/app/tipsmodel.h

src/app/wizardview/components/AdvancedAccountSettings.qml

...app/wizardview/components/ConnectToAccountManagerPage.qml