MTMD - Remove Llava

[SignalRT]

Llama.cpp is in the way to deprecate llava and the library that will manage multi modal models is mdmd.

ggml-org/llama.cpp#13012

This should address the usage of modern multimodal models.

The action plan:

• Remove llava libraries and generate mtmd libraries.
• Change LlamaSharp to use mtmd. In progress
• Modify unit test
• Upgrade samples with modern models
• Upgrade documentation
• Upgrade nuget packages