Support for half/float16 (and bfloat16?)

[LaurentMazare]

Thanks for these great blas bindings, these are super convenient. Apologies if f16/bf16 support has been mentioned in the past, I haven't found any related issue.

Do you think it would be possible to have support for f16 support in this crate? mkl supports these (half/f16, bf16). The half crate provide nice types for f16/bf16 on the rust side so it would be nice to have some hgemm functions that would operate on these. Happy to help in any way I can.

(for context we're working on some ML framework crate and it would be great to provide mkl as an efficient cpu backend)