feat: add tree view in chart of accounts component

Add tree view for GL accounts in chart of accounts component.

src/app/accounting/chart-of-accounts/gl-account-tree.service.spec.ts

@@ -0,0 +1,15 @@
+import { TestBed, inject } from '@angular/core/testing';
+
+import { GlAccountTreeService } from './gl-account-tree.service';
+
+describe('GlAccountTreeService', () => {
+  beforeEach(() => {
+    TestBed.configureTestingModule({
+      providers: [GlAccountTreeService]
+    });
+  });
+
+  it('should be created', inject([GlAccountTreeService], (service: GlAccountTreeService) => {
+    expect(service).toBeTruthy();
+  }));
+});