Add maxLength to content-subject/-body

src/app/components/creator/content-creator/content-creator.component.html

 <form>
 <mat-form-field class="input-block">
-  <input matInput #subject [(ngModel)]="content.subject" placeholder="{{'content.subject' | translate}}" name="subject">
+  <input matInput #subject [(ngModel)]="content.subject" placeholder="{{'content.subject' | translate}}" name="subject"
+  maxlength="20">
 </mat-form-field>
 <app-markdown-toolbar textareaId="content-text-body"></app-markdown-toolbar>
 <mat-form-field class="input-block">
     <textarea matInput #body [(ngModel)]="content.body" placeholder="{{'content.body' | translate}}" name="body"
-              matTextareaAutosize matAutosizeMinRows="3" matAutosizeMaxRows="8"></textarea>
+              matTextareaAutosize matAutosizeMinRows="3" matAutosizeMaxRows="8" maxlength="100"></textarea>
 </mat-form-field>
 <markdown [data]="content.body"></markdown>
 <mat-form-field>