Tweak frontpage

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

 <div fxLayout="column" fxLayoutAlign="center center" fxlayoutgap="50px" fxFill>
 <form (ngSubmit)="joinRoom(roomId.value)">
   <div fxLayout="row" fxLayoutAlign="center" fxLayoutGap="10px">
-    <mat-form-field>
+    <mat-form-field (keyup.enter)="onEnter()">
       <input matInput #roomId type="text" pattern="[0-9 ]*" inputmode="numeric" min="00000000" max="99999999"
              onkeydown="if(this.value.length - (this.value.split(' ').length -1) === 8 && event.keyCode != 8) return false;
                         if(this.value.length === 4 && event.keyCode != 8) this.value = this.value + ' ';"