Fix: Username unique index was case sensitive and this allowed duplicate names.

Feature: Moved temporal products into their own module and reverted the products module

bookie/src/app/core/product.ts

@@ -6,7 +6,6 @@ import { Tax } from './tax';
 export class Product {
   id: string | undefined;
   versionId?: string;
-  code: number;
   name: string;
   units: string;
   menuCategory?: MenuCategory;
@@ -21,12 +20,11 @@ export class Product {
   enabled: boolean;
   tax: Tax;
 
-  validFrom?: string;
-  validTill?: string;
+  validFrom: string | null;
+  validTill: string | null;
 
   public constructor(init?: Partial<Product>) {
     this.id = undefined;
-    this.code = 0;
     this.name = '';
     this.units = '';
     this.price = 0;
@@ -36,6 +34,8 @@ export class Product {
     this.isActive = true;
     this.sortOrder = 0;
     this.enabled = true;
+    this.validFrom = null;
+    this.validTill = null;
     this.tax = new Tax();
     Object.assign(this, init);
   }