[Clean-up] Planned removal of the `max_size` argument

- Replace deprecated `"feature_extractor_type": "DetrFeatureExtractor"` with `"image_processor_type": "DetrImageProcessor"`
- Remove deprecated `max_size` and replace `size` with a `Dict`

preprocessor_config.json

@@ -1,18 +1,20 @@
 {
-    "do_normalize": true,
-    "do_resize": true,
-    "feature_extractor_type": "DetrFeatureExtractor",
-    "format": "coco_detection",
-    "image_mean": [
-      0.485,
-      0.456,
-      0.406
-    ],
-    "image_std": [
-      0.229,
-      0.224,
-      0.225
-    ],
-    "max_size": 1333,
-    "size": 800
-  }
+  "do_normalize": true,
+  "do_resize": true,
+  "image_processor_type": "DetrImageProcessor",
+  "format": "coco_detection",
+  "image_mean": [
+    0.485,
+    0.456,
+    0.406
+  ],
+  "image_std": [
+    0.229,
+    0.224,
+    0.225
+  ],
+  "size": {
+    "longest_edge": 1333,
+    "shortest_edge": 800
+  }
+}