Support for AI21 Jamba-1.5

[vlbosch]

I was wondering whether it is possible to add support for Jamba-1.5-Mini (ai21labs/AI21-Jamba-1.5-Mini). The model seems pretty good for its size and has a large context window that seems to hold up the claimed size, as shown with the RULER Benchmark. Thanks in advance!

EDIT: Direct link to the HF-repo: ai21labs/AI21-Jamba-1.5-Mini

[hg0428]

https://github.com/ml-explore/mlx-examples/issues/1030