Rename AbstractStacksModel.py -> MachineListModel.py since this model includes both abstract machine stacks and regular machines

Add machineCount for displaying the number of machines of a type.

MachineSelectorButton is in use in other places, swapped it out for a new Component MachineListButton.

CURA-9514

resources/qml/PrinterSelector/MachineListButton.qml

@@ -0,0 +1,88 @@
+// Copyright (c) 2018 Ultimaker B.V.
+// Cura is released under the terms of the LGPLv3 or higher.
+
+import QtQuick 2.10
+import QtQuick.Controls 2.3
+
+import UM 1.5 as UM
+import Cura 1.0 as Cura
+
+
+Button
+{
+    id: machineListButton
+
+    width: parent.width
+    height: UM.Theme.getSize("large_button").height
+    leftPadding: UM.Theme.getSize("default_margin").width
+    rightPadding: UM.Theme.getSize("default_margin").width
+    checkable: true
+    hoverEnabled: true
+
+    contentItem: Item
+    {
+        width: machineListButton.width - machineListButton.leftPadding - machineListButton.rightPadding
+        height: UM.Theme.getSize("action_button").height
+
+        UM.ColorImage
+        {
+            id: printerIcon
+            height: UM.Theme.getSize("medium_button").height
+            width: UM.Theme.getSize("medium_button").width
+            color: UM.Theme.getColor("machine_selector_printer_icon")
+            visible: model.machineType == "abstract_machine"
+            source: model.machineType == "abstract_machine" ? UM.Theme.getIcon("PrinterTriple", "medium") : UM.Theme.getIcon("Printer", "medium")
+
+            anchors
+            {
+                left: parent.left
+                verticalCenter: parent.verticalCenter
+            }
+        }
+
+        UM.Label
+        {
+            id: buttonText
+            anchors
+            {
+                left: printerIcon.right
+                right: printerCount.left
+                verticalCenter: parent.verticalCenter
+                leftMargin: UM.Theme.getSize("default_margin").width
+            }
+            text: machineListButton.text
+            font: model.machineType == "abstract_machine" ? UM.Theme.getFont("medium_bold") : UM.Theme.getFont("medium")
+            visible: text != ""
+            elide: Text.ElideRight
+        }
+
+        Rectangle
+        {
+            id: printerCount
+            color: UM.Theme.getColor("background_2")
+            radius: height
+            width: height
+            anchors
+            {
+                right: parent.right
+                top: buttonText.top
+                bottom: buttonText.bottom
+                verticalCenter: parent.verticalCenter
+            }
+            visible: model.machineType == "abstract_machine"
+
+            UM.Label
+            {
+                text: model.machineCount
+                anchors.centerIn: parent
+                font: UM.Theme.getFont("default_bold")
+            }
+        }
+    }
+
+    background: Rectangle
+    {
+        id: backgroundRect
+        color: machineListButton.hovered ? UM.Theme.getColor("action_button_hovered") : "transparent"
+    }
+}