[WIP][V1] Extend beyond image modality and support mixed-modality inference with Llava-OneVision

[ywang96]

Goal of this PR:

• Extends V1 support for multimodal models beyond image modality.
• Infrastructure support non-interleaving mixed-modality inference (e.g, <image><image><video>What are described in these items?).
• Adds V1 support for Llava-OneVision

[github-actions]

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