🗃️(backend) export to docx

We can now export our document to a docx file.
This is done by converting the html to a docx
file using the pypandoc and pandoc library.
We added the "format" param to the
generate-document endpoint, "format" accept
"pdf" or "docx" as value.

src/backend/core/tests/templates/test_api_templates_generate_document.py

@@ -178,3 +178,26 @@ def test_api_templates_generate_document_type_unknown():
             '"unknown" is not a valid choice.',
         ]
     }
+
+
+def test_api_templates_generate_document_export_docx():
+    """Generate pdf document with the body type html."""
+    user = factories.UserFactory()
+
+    client = APIClient()
+    client.force_login(user)
+
+    template = factories.TemplateFactory(is_public=True)
+    data = {"body": "<p>Test body</p>", "body_type": "html", "format": "docx"}
+
+    response = client.post(
+        f"/api/v1.0/templates/{template.id!s}/generate-document/",
+        data,
+        format="json",
+    )
+
+    assert response.status_code == 200
+    assert (
+        response.headers["content-type"]
+        == "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+    )