refractor: accounting module (#300)

* Refractor components.
* Add resolvers.
* Add relative router links.
* Replace mat-icons by font-awesome icons.
* Add comments.

Fixes: #298

src/app/accounting/closing-entries/closing-entries.resolver.ts

@@ -0,0 +1,30 @@
+/** Angular Imports */
+import { Injectable } from '@angular/core';
+import { Resolve } from '@angular/router';
+
+/** rxjs Imports */
+import { Observable } from 'rxjs';
+
+/** Custom Services */
+import { AccountingService } from '../accounting.service';
+
+/**
+ * Closing entries data resolver.
+ */
+@Injectable()
+export class ClosingEntriesResolver implements Resolve<Object> {
+
+  /**
+   * @param {AccountingService} accountingService Accounting service.
+   */
+  constructor(private accountingService: AccountingService) {}
+
+  /**
+   * Returns the gl account closures data.
+   * @returns {Observable<any>}
+   */
+  resolve(): Observable<any> {
+    return this.accountingService.getAccountingClosures();
+  }
+
+}