Render labels using Text.QtRendering on OSX

Fonts were looking a bit to thick on when using `Text.NativeRendering`, so using `Text.QtRendering` instead. After this the font weight looks identical to figma (as far as I can see).

In this commit I also changed all `Label`'s to `UM.Label`'s and removed default properties where I could.

CURA-9154

resources/qml/WelcomePages/WelcomeContent.qml

@@ -4,7 +4,7 @@
 import QtQuick 2.10
 import QtQuick.Controls 2.3
 
-import UM 1.3 as UM
+import UM 1.5 as UM
 import Cura 1.1 as Cura
 
 //
@@ -48,7 +48,7 @@ Item
             width: parent.width
         }
 
-        Label
+        UM.Label
         {
             id: titleLabel
             anchors.horizontalCenter: parent.horizontalCenter
@@ -56,20 +56,16 @@ Item
             text: catalog.i18nc("@label", "Welcome to Ultimaker Cura")
             color: UM.Theme.getColor("primary_button")
             font: UM.Theme.getFont("huge_bold")
-            renderType: Text.NativeRendering
         }
 
-        Label
+        UM.Label
         {
             id: textLabel
             anchors.horizontalCenter: parent.horizontalCenter
             horizontalAlignment: Text.AlignHCenter
             width: titleLabel.width + 2 * UM.Theme.getSize("thick_margin").width
             text: catalog.i18nc("@text", "Please follow these steps to set up Ultimaker Cura. This will only take a few moments.")
-            wrapMode: Text.Wrap
             font: UM.Theme.getFont("medium")
-            color: UM.Theme.getColor("text")
-            renderType: Text.NativeRendering
         }
 
         // Filler item