Merge branch '187-refine-room-list' into 'master'

Resolve "Refine room list"

Closes #187

See merge request arsnova/arsnova-lite!130

src/app/components/shared/room-list/room-list.component.html

@@ -2,13 +2,21 @@
   <div fxLayout="row" fxLayoutAlign="center">
     <mat-progress-spinner *ngIf="isLoading" mode="indeterminate"></mat-progress-spinner>
   </div>
+  <mat-expansion-panel [disabled]="true">
+    <mat-expansion-panel-header>
+      <mat-panel-title>Session-Id</mat-panel-title>
+      <mat-panel-description>Name</mat-panel-description>
+    </mat-expansion-panel-header>
+  </mat-expansion-panel>
+  <mat-divider></mat-divider>
+  <mat-divider></mat-divider>
   <mat-expansion-panel *ngFor="let room of rooms">
     <mat-expansion-panel-header>
       <button mat-button color="accent" routerLink="/{{ baseUrl }}/room/{{ room.shortId }}">
         <mat-icon>input</mat-icon>
       </button>
       <mat-panel-title>
-        {{ room.shortId }}
+        {{ room.shortId.slice(0,4) }} {{  room.shortId.slice(4,8) }}
       </mat-panel-title>
       <mat-panel-description>
         {{ room.name }}