- Refactor `OpenAIServingChat` and add function for loading image
- Move `pillow` dev dependency to common
- Add example chat template for LLaVA model

- Add general guide for using VLMs
- Add LLavA to list of supported models

- Move `ServerRunner` to common file

- Incorrect loading of config (also rename `openai_api` to `image_openai`)
- Incorrect await of stream generator

- Also, use the type definitions from `openai` directly

…ions API and legacy Completions API

- Note that multi modal processing logic has been moved from `LLM` to `LLMEngine`

- Also fix missing arguments to config in `test_llava.py`

- Remove channel conversion and resizing from OpenAI server preprocessing since the image processor in HuggingFace should be able to handle that
- `MultiModalData` is now an abstract class that outputs additional kwargs to be input into the model. This was intially done to support LLaVA-NeXT's `image_size` parameter but can be extended to other models as well.
- The application of image processor is now defined inside `MultiModalData` so that there is no need to extensively edit the engine to support other types of data
- New `MultiModalData` subclasses: `ImagePixelData` and `ImageFeatureData` to better differentiate the two cases of image input
- Refactored LLaVA-1.5 model to make it easier to inherit for defining LLaVA-NeXT model

- Now, `ImagePixelData` only accepts `PIL.Image` input
- Also move `torch` import out of `TYPE_CHECKING` as it is loaded anyways when importing `SamplingParams`

- Note the patch in `ImagePixelData`. To fully leverage the potential of LLaVA-Next, we should allow image of any size, but the feature size would then be variable.

- Note that we now load the images directly instead of from `.pt` files

- These changes are propagated to the child PRs