Introduced Style.svg() Style.png() Style.emoji() and
Style.icon() in Style.qml. Those should be used to
set the source in Images instead of using relative
paths. Usage:
Image {
source: Style.svg("check)
....
Also moved all Singletons inside a new "utils"
folder and made it a QML module, to use
import utils 1.0 instead of relative paths
Closes#3678
