Fix: import script to fit the new structure of voucher table (is_printed field removed, voucher_type != KOT is now assumed to be printed)

Fix: Take-away bill type is now removed
Fix: Table overview now shows the right amounts
Voucher Save and Update should now work
Discounts now working (permissions are not checked)

bookie/src/app/sales/discount/discount-datasource.ts

@@ -0,0 +1,16 @@
+import { DataSource } from '@angular/cdk/collections';
+import { Observable, of as observableOf } from 'rxjs';
+
+export class DiscountDataSource extends DataSource<{name: string, discount: number}> {
+
+  constructor(private data: {name: string, discount: number}[]) {
+    super();
+  }
+
+  connect(): Observable<{name: string, discount: number}[]> {
+    return observableOf(this.data);
+  }
+
+  disconnect() {
+  }
+}