Add shorthand for logging images to tensorboard

Summary:
This is be convenient for the image generation use cases, so users can avoid doing this
```
writer = tb_logger.writer
if writer:
    ...
```

Reviewed By: daniellepintz

Differential Revision: D45995451

fbshipit-source-id: 7c6d0e32ddd935b1e5860c59b5a8c3596da60e84

torchtnt/utils/loggers/tensorboard.py

@@ -134,6 +134,29 @@ def log_hparams(
         if self._writer:
             self._writer.add_hparams(hparams, metrics)
 
+    def log_image(self, *args: Any, **kwargs: Any) -> None:
+        """Add image data to TensorBoard.
+
+
+        Args:
+            *args (Any): Positional arguments passed to SummaryWriter.add_image
+            **kwargs(Any): Keyword arguments passed to SummaryWriter.add_image
+        """
+        writer = self._writer
+        if writer:
+            writer.add_image(*args, **kwargs)
+
+    def log_images(self, *args: Any, **kwargs: Any) -> None:
+        """Add batched image data to summary.
+
+        Args:
+            *args (Any): Positional arguments passed to SummaryWriter.add_images
+            **kwargs(Any): Keyword arguments passed to SummaryWriter.add_images
+        """
+        writer = self._writer
+        if writer:
+            writer.add_images(*args, **kwargs)
+
     def flush(self) -> None:
         """Writes pending logs to disk."""