Changed Marketplace button to no longer use the action button

The actionButton is weirdly named and overly used. That being said, the marketplace button is unique, so
there is little sense in re-using it

resources/qml/MainWindow/MainWindowHeader.qml

@@ -2,6 +2,7 @@
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.7
+import QtQuick.Controls 2.0 as Controls2
 import QtQuick.Controls 1.4
 import QtQuick.Controls.Styles 1.1
 
@@ -73,25 +74,35 @@ Rectangle
     }
 
     // Shortcut button to quick access the Toolbox
-    Cura.ActionButton
+    Controls2.Button
     {
+        id: marketplaceButton
+        text: catalog.i18nc("@action:button", "Marketplace")
+        height: Math.round(0.5 * UM.Theme.getSize("main_window_header").height)
+        onClicked: Cura.Actions.browsePackages.trigger()
+
+        background: Rectangle
+        {
+            radius: UM.Theme.getSize("action_button_radius").width
+            color: "transparent"
+            border.width: UM.Theme.getSize("default_lining").width
+            border.color: UM.Theme.getColor("primary_text")
+        }
+
+        contentItem: Label
+        {
+            id: label
+            text: marketplaceButton.text
+            color: UM.Theme.getColor("primary_text")
+            width: contentWidth
+        }
+
         anchors
         {
             right: accountWidget.left
             rightMargin: UM.Theme.getSize("default_margin").width
             verticalCenter: parent.verticalCenter
         }
-        leftPadding: UM.Theme.getSize("default_margin").width
-        rightPadding: UM.Theme.getSize("default_margin").width
-        text: catalog.i18nc("@action:button", "Marketplace")
-        height: Math.round(0.5 * UM.Theme.getSize("main_window_header").height)
-        color: UM.Theme.getColor("main_window_header_secondary_button_background_active")
-        hoverColor: UM.Theme.getColor("main_window_header_secondary_button_background_hovered")
-        outlineColor: UM.Theme.getColor("main_window_header_secondary_button_outline_active")
-        outlineHoverColor: UM.Theme.getColor("main_window_header_secondary_button_outline_hovered")
-        textColor: UM.Theme.getColor("main_window_header_secondary_button_text_active")
-        textHoverColor: UM.Theme.getColor("main_window_header_secondary_button_text_hovered")
-        onClicked: Cura.Actions.browsePackages.trigger()
     }
 
     AccountWidget

resources/themes/cura-light/theme.json

@@ -98,13 +98,6 @@
         "main_window_header_button_background_inactive": [255, 255, 255, 0],
         "main_window_header_button_background_hovered": [255, 255, 255, 102],
 
-        "main_window_header_secondary_button_text_active": [255, 255, 255, 255],
-        "main_window_header_secondary_button_text_hovered": [10, 8, 80, 255],
-        "main_window_header_secondary_button_background_active": [255, 255, 255, 0],
-        "main_window_header_secondary_button_background_hovered": [255, 255, 255, 255],
-        "main_window_header_secondary_button_outline_active": [255, 255, 255, 255],
-        "main_window_header_secondary_button_outline_hovered": [255, 255, 255, 255],
-
         "account_widget_outline_active": [70, 66, 126, 255],
 
         "machine_selector_bar": [31, 36, 39, 255],