Update Dialog imports to remove version

Update FileDialogs selectExisting -> fileMode and folder -> currentFolder

CURA-8640

resources/qml/Cura.qml

@@ -3,7 +3,8 @@
 
 import QtQuick 2.7
 import QtQuick.Controls 2.15
-import QtQuick.Dialogs 6.0
+import QtQuick.Dialogs
+
 import UM 1.5 as UM
 import Cura 1.1 as Cura
 

resources/qml/MachineSettings/NumericTextFieldWithUnit.qml

@@ -1,7 +1,7 @@
 // Copyright (c) 2020 Ultimaker B.V.
 // Cura is released under the terms of the LGPLv3 or higher.
 
-import QtQuick 2.10
+import QtQuick 2.15
 import QtQuick.Controls 2.3
 
 import UM 1.5 as UM

resources/qml/Preferences/Materials/MaterialsBrandSection.qml

@@ -2,7 +2,7 @@
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.7
-import QtQuick.Controls 1.4
+import QtQuick.Controls 2.1
 import QtQuick.Layouts 1.3
 
 import UM 1.5 as UM

resources/qml/Preferences/Materials/MaterialsList.qml

@@ -2,8 +2,8 @@
 // Uranium is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.7
-import QtQuick.Controls 1.4
 import QtQuick.Layouts 1.3
+import QtQuick.Dialogs
 
 import UM 1.2 as UM
 import Cura 1.0 as Cura

resources/qml/Preferences/Materials/MaterialsPage.qml

@@ -3,7 +3,7 @@
 
 import QtQuick 2.7
 import QtQuick.Controls 2.15
-import QtQuick.Dialogs 6.0
+import QtQuick.Dialogs
 
 import UM 1.5 as UM
 import Cura 1.5 as Cura
@@ -226,9 +226,9 @@ UM.ManagementPage
         {
             id: importMaterialDialog
             title: catalog.i18nc("@title:window", "Import Material")
-            selectExisting: true
+            fileMode: FileDialog.OpenFile
             nameFilters: Cura.ContainerManager.getContainerNameFilters("material")
-            folder: CuraApplication.getDefaultPath("dialog_material_path")
+            currentFolder: CuraApplication.getDefaultPath("dialog_material_path")
             onAccepted:
             {
                 const result = Cura.ContainerManager.importMaterialContainer(fileUrl);
@@ -254,9 +254,9 @@ UM.ManagementPage
         {
             id: exportMaterialDialog
             title: catalog.i18nc("@title:window", "Export Material")
-            selectExisting: false
+            fileMode: FileDialog.SaveFile
             nameFilters: Cura.ContainerManager.getContainerNameFilters("material")
-            folder: CuraApplication.getDefaultPath("dialog_material_path")
+            currentFolder: CuraApplication.getDefaultPath("dialog_material_path")
             onAccepted:
             {
                 const result = Cura.ContainerManager.exportContainer(base.currentItem.root_material_id, selectedNameFilter, fileUrl);

resources/qml/Preferences/Materials/MaterialsSyncDialog.qml

@@ -3,9 +3,10 @@
 
 import QtQuick 2.15
 import QtQuick.Controls 2.15
-import QtQuick.Dialogs 6.0
+import QtQuick.Dialogs
 import QtQuick.Layouts 1.15
 import QtQuick.Window 2.1
+
 import Cura 1.1 as Cura
 import UM 1.5 as UM
 

resources/qml/Preferences/Materials/MaterialsTypeSection.qml

@@ -2,7 +2,7 @@
 // Uranium is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.7
-import QtQuick.Controls 1.4
+import QtQuick.Controls 2.4
 import QtQuick.Layouts 1.3
 
 import UM 1.5 as UM

resources/qml/Preferences/Materials/MaterialsView.qml

@@ -3,8 +3,8 @@
 
 import QtQuick 2.7
 import QtQuick.Controls 2.15
-import QtQuick.Dialogs 6.0
 import QtQuick.Layouts 1.3
+import QtQuick.Dialogs
 
 import UM 1.5 as UM
 import Cura 1.0 as Cura

resources/qml/Preferences/ProfilesPage.qml

@@ -4,7 +4,7 @@
 import QtQuick 2.7
 import QtQuick.Controls 2.15
 import QtQuick.Layouts 1.3
-import QtQuick.Dialogs 6.0
+import QtQuick.Dialogs
 
 import UM 1.5 as UM
 import Cura 1.6 as Cura
@@ -349,9 +349,9 @@ UM.ManagementPage
         {
             id: exportDialog
             title: catalog.i18nc("@title:window", "Export Profile")
-            selectExisting: false
+            fileMode: FileDialog.SaveFile
             nameFilters: base.qualityManagementModel.getFileNameFilters("profile_writer")
-            folder: CuraApplication.getDefaultPath("dialog_profile_path")
+            currentFolder: CuraApplication.getDefaultPath("dialog_profile_path")
             onAccepted:
             {
                 var result = Cura.ContainerManager.exportQualityChangesGroup(base.currentItem.quality_changes_group,
@@ -414,9 +414,9 @@ UM.ManagementPage
         {
             id: importDialog
             title: catalog.i18nc("@title:window", "Import Profile")
-            selectExisting: true
+            fileMode: FileDialog.OpenFile
             nameFilters: base.qualityManagementModel.getFileNameFilters("profile_reader")
-            folder: CuraApplication.getDefaultPath("dialog_profile_path")
+            currentFolder: CuraApplication.getDefaultPath("dialog_profile_path")
             onAccepted:
             {
                 var result = Cura.ContainerManager.importProfile(fileUrl);