convert_dinov2: tweak command-line args

i.e. mimic the other conversion scripts

scripts/conversion/convert_dinov2.py

@@ -1,4 +1,5 @@
 import argparse
+from pathlib import Path
 
 import torch
 
@@ -124,12 +125,35 @@ def convert_dinov2_facebook(weights: dict[str, torch.Tensor]) -> None:
 
 def main() -> None:
     parser = argparse.ArgumentParser()
-    parser.add_argument("--weights_path", type=str, required=True)
-    parser.add_argument("--output_path", type=str, required=True)
+    parser.add_argument(
+        "--from",
+        type=str,
+        required=True,
+        dest="source_path",
+        help=(
+            "Official checkpoint from https://github.com/facebookresearch/dinov2"
+            " e.g. /path/to/dinov2_vits14_pretrain.pth"
+        ),
+    )
+    parser.add_argument(
+        "--to",
+        type=str,
+        dest="output_path",
+        default=None,
+        help=(
+            "Path to save the converted model. If not specified, the output path will be the source path with the"
+            " extension changed to .safetensors."
+        ),
+    )
+    parser.add_argument("--half", action="store_true", dest="half")
     args = parser.parse_args()
 
-    weights = torch.load(args.weights_path)  # type: ignore
+    weights = torch.load(args.source_path)  # type: ignore
     convert_dinov2_facebook(weights)
+    if args.half:
+        weights = {key: value.half() for key, value in weights.items()}
+    if args.output_path is None:
+        args.output_path = f"{Path(args.source_path).stem}.safetensors"
     save_to_safetensors(path=args.output_path, tensors=weights)