added missing trasnlation

Author: Shayan1375

src/app/layout/components/header/header.component.html

@@ -10,16 +10,16 @@
       >
         <mat-option (click)="getActuatorInfo()">
           <fa-icon class="circle" size="lg" [fixedWidth]="true" [icon]="'info'"></fa-icon>
-          About
+          {{ 'APPLAYOUT.HEADER.ABOUT' | translate }}
         </mat-option>
         <mat-option (click)="logout()">
           <fa-icon class="circle" size="lg" [fixedWidth]="true" [icon]="'sign-out-alt'"></fa-icon>
-          Logout
+          {{ 'APPLAYOUT.HEADER.LOGOUT' | translate }}
         </mat-option>
       </mat-select>
     </mat-form-field>
     <span class="link-like" (click)="navigateToProposalPortal()">
-      Antragsportal
+      {{ 'APPLAYOUT.HEADER.PROPOSAL_PORTAL' | translate }}
       <fa-icon size="1x" icon="external-link-alt"></fa-icon>
     </span>
   </div>

src/assets/i18n/de.json

@@ -5,6 +5,11 @@
     },
     "TOGGLE": {
       "LABEL": "Seitennavigation umschalten"
+    },
+    "HEADER": {
+      "PROPOSAL_PORTAL": "Antragsportal",
+      "ABOUT": "Über das Portal",
+      "LOGOUT": "Abmelden"
     }
   },
   "DATAQUERY": {