Feature: Lazy loading

Lazy loaded everything
TODO: The cash flow module when clicking on sub-links, it reloads the whole page, it needs to be diagnosed and fixed, this problem also exists in the other modules
TODO: Rename folders and modules such as account to accounts to match the url

overlord/src/app/ledger/ledger.ts

@@ -1,4 +1,4 @@
-import {Account} from '../account/account';
+import {Account} from '../core/account';
 
 export class LedgerItem {
   date: string;