title: ngbTimepicker not working in ngbmodal with reactive form
body: <p>I got an error (<strong>There is no directive with "exportAs" set to "NgbTimepicker"</strong>) when trying to use <strong>NgbTimepicker</strong> in a reactive form in a modal.</p>
  
  <p>In <strong>app.module.ts</strong>, I import <strong>ngbModule</strong>:</p>
  
  <pre><code>import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
  
  @NgModule({
  declarations: [
    ...
  ],
  imports: [
     ...
     NgbModule.forRoot(),
  ],
  providers: [],
  bootstrap: [AppComponent]
  })
  </code></pre>
  
  <p>In the <strong>page.component.ts</strong>,</p>
  
  <pre><code>import { NgbModal, NgbTimepicker} from '@ng-bootstrap/ng-bootstrap';
  
  ...
  
   workingStartTime: [null, Validators.compose([Validators.required])],
  </code></pre>
  
  <p>In the <strong>page.component.html</strong></p>
  
  <pre><code> &lt;input type="text" formControlName="workingStartTime" placeholder=""
          NgbTimepicker #timepicker="NgbTimepicker (click)="timepicker.toggle()"&gt;
  </code></pre>
  
  <p>I spent some hours without success looking what is wrong. Am i doing something wrong? Thanks.</p>