Report image rendering fix (#5907)

* Allow different image variations to be rendered in when using a part image in a report

* Use preview image in default test report

* Fix api_version

- Missed in https://github.com/inventree/InvenTree/pull/5906

* Update docstring

* Add similar functionality for company_image tag

* Update report documentation

* base-64 encode images for rendering in reports

- Allows image manipulation operations to be performed on the images
- Avoids any file pathing issues

* Update docs

* Fix unit tests

* More unit test fixes

* More unit test

* Handle missing file

* Instrument unit test

- Trying to determine what is going on here

* Fix for image resize

* Translate error messages

* Update default report templates

- Specify image size

InvenTree/label/tests.py

@@ -106,7 +106,7 @@ class LabelTest(InvenTreeAPITestCase):
         <!-- Test InvenTree URL -->
         url: {{ qr_url|safe }}
         <!-- Test image URL generation -->
-        image: {% part_image part %}
+        image: {% part_image part width=128 %}
         <!-- Test InvenTree logo -->
         logo: {% logo_image %}
         </html>
@@ -154,8 +154,9 @@ class LabelTest(InvenTreeAPITestCase):
         self.assertIn(f"part: {part_pk} - {part_name}", content)
         self.assertIn(f'data: {{"part": {part_pk}}}', content)
         self.assertIn(f'http://testserver/part/{part_pk}/', content)
-        self.assertIn("img/blank_image.png", content)
-        self.assertIn("img/inventree.png", content)
+
+        # Check that a encoded image has been generated
+        self.assertIn('data:image/png;charset=utf-8;base64,', content)
 
     def test_metadata(self):
         """Unit tests for the metadata field."""