Improve 404 navigation and styling

src-ui/src/app/components/common/logo/logo.component.ts

@@ -0,0 +1,18 @@
+import { Component, Input } from '@angular/core'
+
+@Component({
+  selector: 'app-logo',
+  templateUrl: './logo.component.html',
+  styleUrls: ['./logo.component.scss'],
+})
+export class LogoComponent {
+  @Input()
+  extra_classes: string
+
+  @Input()
+  height = '6em'
+
+  getClasses() {
+    return ['logo'].concat(this.extra_classes).join(' ')
+  }
+}