Update Icons

Subdivided the new icons in 3 size categories. As requested by UX
Used the company naming scheme for uniformity and easy recognition.

Known issues:
- Top/Bottom category wasn't taken into account by UX at the time. Since
 this is a recent addition. Both the Walls and Top/Bottom will be updated.
- Cloud/Network connection icons 12px don't render correctly. Due to the
 theme-ing.
- Extruder Icons do not render correctly.

CURA-8010_new_icons

resources/qml/ViewOrientationControls.qml

@@ -18,7 +18,7 @@ Row
 
     ViewOrientationButton
     {
-        iconSource: UM.Theme.getIcon("view_3d")
+        iconSource: UM.Theme.getIcon("View3D")
         onClicked: Cura.Actions.view3DCamera.trigger()
 
         UM.TooltipArea
@@ -31,7 +31,7 @@ Row
 
     ViewOrientationButton
     {
-        iconSource: UM.Theme.getIcon("view_front")
+        iconSource: UM.Theme.getIcon("ViewFront")
         onClicked: Cura.Actions.viewFrontCamera.trigger()
 
         UM.TooltipArea
@@ -44,7 +44,7 @@ Row
 
     ViewOrientationButton
     {
-        iconSource: UM.Theme.getIcon("view_top")
+        iconSource: UM.Theme.getIcon("ViewTop")
         onClicked: Cura.Actions.viewTopCamera.trigger()
 
         UM.TooltipArea
@@ -57,7 +57,7 @@ Row
 
     ViewOrientationButton
     {
-        iconSource: UM.Theme.getIcon("view_left")
+        iconSource: UM.Theme.getIcon("ViewLeft")
         onClicked: Cura.Actions.viewLeftSideCamera.trigger()
 
         UM.TooltipArea
@@ -70,7 +70,7 @@ Row
 
     ViewOrientationButton
     {
-        iconSource: UM.Theme.getIcon("view_right")
+        iconSource: UM.Theme.getIcon("ViewRight")
         onClicked: Cura.Actions.viewRightSideCamera.trigger()
 
         UM.TooltipArea