Rename cod-btn into cod-button.

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

@@ -1,7 +1,7 @@
 <div class="left">
     <button type="button"
             (click)="sideMenu.open()"
-            class="cod-btn icon"
+            class="cod-button icon"
             matTooltip="Click to show side menu" 
             matRipple 
             i18n-matTooltip>
@@ -20,7 +20,7 @@
 <div class="right">
     @if (isAuthenticated) {
         <button type="button"
-                class="cod-btn icon"
+                class="cod-button icon"
                 [matMenuTriggerFor]="authenticatedUserMenu" 
                 matRipple>
             <mat-icon>more_vert</mat-icon>
@@ -38,7 +38,7 @@
             </div>
         </mat-menu>
     } @else {
-        <a [routerLink]="['/login']" class="cod-btn" matRipple i18n>Login</a>
+        <a [routerLink]="['/login']" class="cod-button" matRipple i18n>Login</a>
     }
 </div>
 <app-side-menu #sideMenu></app-side-menu>