[DNM] Complex image type handling

[isaacbmiller]

Inspired by #1763 and to close #1767.

Goal is to support images inside arbitrary pydantic objects and to eventually make it easy to add support for other modalities.

[JehandadK]

Suggested change

	" images: List[dspy.Image] = dspy.InputField(desc=\"An image\")\n",
	" images: List[dspy.Image] = dspy.InputField(desc=\"A list of images\")\n",

[JehandadK]

Thanks for the PR @isaacbmiller. I tried this branch with this signature and sharing relevant logs here with you:

class CreateTitleAndDescription(dspy.Signature):
    """Taking in a list of images and a category tree to output title, description and attributes."""

    images: List[dspy.Image] = dspy.InputField(desc="list of images about the item")
    categories: str = dspy.InputField(desc="category tree of the item")
    title: str = dspy.OutputField(desc=title_desc)
    description: str = dspy.OutputField(desc=description_desc)

    {
      'role': 'user',
      'content': '[[ ## images ## ]]\n["https://static-sd.mercdn.net/photos/m34859626959_1.jpg", "https://static-sd.mercdn.net/photos/m34859626959_2.jpg", "https://static-sd.mercdn.net/photos/m34859626959_3.jpg"]\n\n[[ ## categories ## ]]\nゲーム・おもちゃ・グッズ > トレーディングカード\n\nRespond with the corresponding output fields, starting with the field `[[ ## title ## ]]`, then `[[ ## description ## ]]`, and then ending with the marker for `[[ ## completed ## ]]`.'
    }