Docs updates for HUB, YOLOv4, YOLOv7, NAS (#3174)

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

docs/reference/yolo/utils/callbacks/dvc.md

@@ -0,0 +1,54 @@
+---
+description: Explore Ultralytics YOLO Utils DVC Callbacks such as logging images, plots, confusion matrices, and training progress.
+keywords: Ultralytics, YOLO, Utils, DVC, Callbacks, images, plots, confusion matrices, training progress
+---
+
+# _logger_disabled
+---
+:::ultralytics.yolo.utils.callbacks.dvc._logger_disabled
+<br><br>
+
+# _log_images
+---
+:::ultralytics.yolo.utils.callbacks.dvc._log_images
+<br><br>
+
+# _log_plots
+---
+:::ultralytics.yolo.utils.callbacks.dvc._log_plots
+<br><br>
+
+# _log_confusion_matrix
+---
+:::ultralytics.yolo.utils.callbacks.dvc._log_confusion_matrix
+<br><br>
+
+# on_pretrain_routine_start
+---
+:::ultralytics.yolo.utils.callbacks.dvc.on_pretrain_routine_start
+<br><br>
+
+# on_pretrain_routine_end
+---
+:::ultralytics.yolo.utils.callbacks.dvc.on_pretrain_routine_end
+<br><br>
+
+# on_train_start
+---
+:::ultralytics.yolo.utils.callbacks.dvc.on_train_start
+<br><br>
+
+# on_train_epoch_start
+---
+:::ultralytics.yolo.utils.callbacks.dvc.on_train_epoch_start
+<br><br>
+
+# on_fit_epoch_end
+---
+:::ultralytics.yolo.utils.callbacks.dvc.on_fit_epoch_end
+<br><br>
+
+# on_train_end
+---
+:::ultralytics.yolo.utils.callbacks.dvc.on_train_end
+<br><br>