whitelabeling: change welcomePage to take into account ui customization

resources/icons/Trash_Black_24dp.svg

resources/icons/backup.svg

resources/icons/jami-logo-icon.svg

resources/icons/jami_id_logo.svg

resources/images/BG-DarkMode-ID_Jami.png

resources/images/BG-LightMode-ID_Jami.png

src/app/commoncomponents/JamiIdentifier.qml

src/app/commoncomponents/RoundedBorderRectangle.qml

src/app/constant/JamiStrings.qml

src/app/constant/JamiTheme.qml

src/app/mainview/components/BackupTipBox.qml

src/app/mainview/components/CachedImage.qml

src/app/mainview/components/CustomizeTipBox.qml

src/app/mainview/components/InformativeTipBox.qml

src/app/mainview/components/TipBox.qml

src/app/mainview/components/TipsRow.qml

src/app/mainview/components/WelcomeInfo.qml

src/app/mainview/components/WelcomeLogo.qml

src/app/mainview/components/WelcomePage.qml

src/app/settingsview/components/ManageAccountPage.qml