Add InstructLab models

[Michael Clifford]

We should include the following 2 models into the model catalog. Also add them to the summarizer and chat recipes model list.

granite-7b-lab

• https://huggingface.co/instructlab/granite-7b-lab-GGUF
• Apache 2.0
• Requires chat_format=openchat

merlinite-7b-lab

• https://huggingface.co/instructlab/merlinite-7b-lab-GGUF
• Apache 2.0
• Requires chat_format=openchat

I've tested them with the llamacpp_python server image as well as the chat and summarizer recipes locally. They appear to work. Was not able to test them yet in AI Lab.