feat(demo): add landing page with docs (#1951)

docs/app/@theme/components/header/header.component.ts

@@ -0,0 +1,52 @@
+/**
+ * @license
+ * Copyright Akveo. All Rights Reserved.
+ * Licensed under the MIT License. See License.txt in the project root for license information.
+ */
+
+import { Component, HostBinding, Input, OnDestroy } from '@angular/core';
+import { takeWhile } from 'rxjs/operators';
+import { NbSidebarService } from '@nebular/theme';
+
+/*import { NgxAnalytics } from '../../services/analytics.service';*/
+import { NgxVersionService } from '../../services/version.service';
+import { HeaderMenuService } from '../../../@core/data/service/header-menu.service';
+
+@Component({
+  selector: 'ngx-landing-header',
+  styleUrls: ['./header.component.scss'],
+  templateUrl: './header.component.html',
+})
+export class NgxLandingHeaderComponent implements OnDestroy {
+
+  private alive = true;
+
+  @HostBinding('class.docs-page') @Input() isDocs = false;
+
+  @Input() sidebarTag: string = '';
+
+  currentVersion: string;
+  headerMenu = [];
+
+  constructor(/*private analytics: NgxAnalytics,*/
+              private sidebarService: NbSidebarService,
+              private versionService: NgxVersionService,
+              private headerMenuService: HeaderMenuService) {
+    this.currentVersion = this.versionService.getNgxVersion();
+
+    this.headerMenuService.getHeaderMenu()
+      .pipe(takeWhile(() => this.alive ))
+      .subscribe((headerMenu) => this.headerMenu = headerMenu);
+  }
+
+  trackEmailClick() {
+  }
+
+  toggleSidebar() {
+    this.sidebarService.toggle(false, this.sidebarTag);
+  }
+
+  ngOnDestroy() {
+    this.alive = false;
+  }
+}