contact form JS separation

templates/contacts/form.html

@@ -157,16 +157,5 @@
     </div>
 </div>
 
-<script>
-function previewAvatar(event) {
-    const [file] = event.target.files;
-    if (file) {
-        const reader = new FileReader();
-        reader.onload = function(e) {
-            document.getElementById('avatarPreview').src = e.target.result;
-        };
-        reader.readAsDataURL(file);
-    }
-}
-</script>
+<script src="{{ url_for('static', filename='js/avatar-preview.js') }}"></script>
 {% endblock %}