Resolve "Embed a Youtube video on the home page"

Closes #287 (closed)

src/app/components/home/_dialogs/demo-video/demo-video.component.html

-<p>
-  demo-video works!
-</p>
+<div class="video" fxLayout="row" fxLayoutAlign="center">
+  <h2 [ngClass]="{'mobileText': deviceType === 'mobile', 'desktopText': deviceType === 'desktop'}">Demo Video</h2>
+  <iframe [ngClass]="{'mobileFrame': deviceType === 'mobile', 'desktopFrame': deviceType === 'desktop'}" src="https://www.youtube.com/embed/gq7LGp5HNIU?autoplay=1" frameborder="0"
+          allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+  <button [ngClass]="{'mobileButton': deviceType === 'mobile', 'desktopButton': deviceType === 'desktop'}" mat-raised-button (click)="closeDialog()">
+    <mat-icon >exit_to_app</mat-icon>
+  </button>
+</div>