Enable DnD for Company image

- Can actually use the existing form to do partial upload!
- Generecise the drag-and-drop upload function
- Remove some (now unnecessary) Python View code

InvenTree/part/templates/part/part_base.html

@@ -13,17 +13,14 @@
 <div class="col-sm-6">
     <div class="media">
       <div class="media-left">
-        <form id='upload-photo' method='post' action="{% url 'part-image-upload' part.id %}">
-            <div class='dropzone' id='part-thumb'>
+        <div class='dropzone' id='part-thumb'>
                 <img class="part-thumb"
                 {% if part.image %}
                 src="{{ part.image.url }}"
                 {% else %}
                 src="{% static 'img/blank_image.png' %}"
                 {% endif %}/>
-            </div>
-                {% csrf_token %}
-        </form>
+        </div>
       </div>
     <div class="media-body">
         <h4>
@@ -102,34 +99,16 @@
 {% block js_ready %}
 {{ block.super }}
 
-    $('#part-thumb').on('drop', function(event) {
-
-        var transfer = event.originalEvent.dataTransfer;
-
-        var formData = new FormData();
-
-        if (isFileTransfer(transfer)) {
-            formData.append('image_file', transfer.files[0]);
-        } else if (isOnlineTransfer(transfer)) {
-            formData.append('image_url', getImageUrlFromTransfer(transfer));
-        } else {
-            console.log('Unknown transfer');
-            return;
-        }
- 
-        inventreeFormDataUpload(
-            "{% url 'part-image-upload' part.id %}",
-            formData,
-            {
-                success: function(data, status, xhr) {
-                    location.reload();
-                },
-                error: function(xhr, status, error) {
-                    showAlertDialog('Error uploading image', renderErrorMessage(xhr));
-                }
+    enableDragAndDrop(
+        '#part-thumb',
+        "{% url 'part-image' part.id %}",
+        {
+            label: 'image',
+            success: function(data, status, xhr) {
+                location.reload();
             }
-        );
-    });
+        }
+    );
 
     $("#show-qr-code").click(function() {
         launchModalForm(