cpp-builder: Replace deprecated DataSet with DataSource

- Field TdxBackendDataSetCollectionItem.DataSet is deprecated.
  This PR replaces it with DataSource.
  See: https://docs.devexpress.com/VCL/dxBackend.ConnectionString.JSON.DataSet.TdxBackendDataSetCollectionItem.DataSet
  https://docs.devexpress.com/VCL/dxBackend.ConnectionString.JSON.DataSet.TdxBackendDataSetCollectionItem.DataSource.
- Remove the unused SQLite database connection.
- Cleanup the form layout and layout manager.

Author: NickVolynkin

CPB/uMainForm.dfm

@@ -1,10 +1,11 @@
 object MainForm: TMainForm
   Left = 0
   Top = 0
+  Width = 657
+  Height = 464
+  AutoScroll = True
   AutoSize = True
   Caption = 'DevExpress Example - Filter Data Records in a Report'
-  ClientHeight = 425
-  ClientWidth = 641
   Color = clBtnFace
   Font.Charset = DEFAULT_CHARSET
   Font.Color = clWindowText
@@ -21,7 +22,7 @@ object MainForm: TMainForm
     AutoSize = True
     object btnPreview: TcxButton
       Left = 12
-      Top = 24
+      Top = 12
       Width = 557
       Height = 25
       Caption = 'Preview Report'
@@ -30,12 +31,12 @@ object MainForm: TMainForm
     end
     object cxGrid1: TcxGrid
       Left = 12
-      Top = 56
+      Top = 44
       Width = 557
       Height = 345
       TabOrder = 1
       object gvProducts: TcxGridDBTableView
-        DataController.DataSource = DataSource1
+        DataController.DataSource = dsProducts
         OptionsData.CancelOnExit = False
         OptionsData.Deleting = False
         OptionsData.DeletingConfirmation = False
@@ -84,34 +85,27 @@ object MainForm: TMainForm
       Index = -1
     end
     object liPreview: TdxLayoutItem
-      Parent = dxLayoutGroup2
+      Parent = dxButtons
       CaptionOptions.Text = 'btnViewReport'
       CaptionOptions.Visible = False
       Control = btnPreview
       ControlOptions.OriginalHeight = 25
-      ControlOptions.OriginalWidth = 193
+      ControlOptions.OriginalWidth = 557
       ControlOptions.ShowBorder = False
       Index = 0
     end
     object dxLayoutLabeledItem1: TdxLayoutLabeledItem
       CaptionOptions.Text = 'Label'
       Index = -1
     end
-    object dxLayoutGroup1: TdxLayoutGroup
-      Parent = dxLayoutGroup3
+    object dxButtons: TdxLayoutGroup
+      Parent = dxLayoutControl1Group_Root
       CaptionOptions.Text = 'New Group'
       CaptionOptions.Visible = False
       ShowBorder = False
       Index = 0
     end
-    object dxLayoutGroup2: TdxLayoutGroup
-      Parent = dxLayoutGroup3
-      CaptionOptions.Text = 'New Group'
-      CaptionOptions.Visible = False
-      ShowBorder = False
-      Index = 1
-    end
-    object dxLayoutItem1: TdxLayoutItem
+    object dxGrid: TdxLayoutItem
       Parent = dxLayoutControl1Group_Root
       AlignHorz = ahLeft
       CaptionOptions.Text = 'cxGrid1'
@@ -122,13 +116,6 @@ object MainForm: TMainForm
       ControlOptions.ShowBorder = False
       Index = 1
     end
-    object dxLayoutGroup3: TdxLayoutGroup
-      Parent = dxLayoutControl1Group_Root
-      CaptionOptions.Text = 'New Group'
-      ItemIndex = 1
-      ShowBorder = False
-      Index = 0
-    end
   end
   object dxReport1: TdxReport
     ReportName = 'Product List Report'
@@ -381,15 +368,9 @@ object MainForm: TMainForm
   object dxReportDataConnectionManager: TdxBackendDataConnectionManager
     Left = 40
     Top = 144
-    object ReportsNWindConnectionString: TdxBackendDatabaseSQLConnection
-      DisplayName = 'NWindConnectionString'
-      ConnectionString = 
-        'XpoProvider=SQLite; Data Source=|DataDirectory|\..\..\..\nwind.d' +
-        'b; Mode=ReadOnly'
-    end
     object NWindMemDataConnection: TdxBackendDataSetJSONConnection
       object NWindMemDataConnectionItem1: TdxBackendDataSetCollectionItem
-        DataSet = mdProducts
+        DataSource = dsProducts
         DataSetAlias = 'Products'
       end
     end
@@ -400,7 +381,7 @@ object MainForm: TMainForm
     Left = 88
     Top = 144
   end
-  object DataSource1: TDataSource
+  object dsProducts: TDataSource
     DataSet = mdProducts
     Left = 88
     Top = 192

CPB/uMainForm.h

@@ -68,11 +68,10 @@ class TMainForm : public TForm
 	TdxLayoutGroup *dxLayoutGroup3;
 	TdxReport *dxReport1;
 	TdxBackendDataConnectionManager *dxReportDataConnectionManager;
-	TdxBackendDatabaseSQLConnection *ReportsNWindConnectionString;
 	TdxBackendDataSetJSONConnection *NWindMemDataConnection;
 	TdxBackendDataSetCollectionItem *NWindMemDataConnectionItem1;
 	TdxSkinController *dxSkinController1;
-	TDataSource *DataSource1;
+	TDataSource *dsProducts;
 	TdxMemData *mdProducts;
 	TIntegerField *mdProductsProductID;
 	TWideStringField *mdProductsProductName;