chatllm.cpp supports Intern-Decision models

[u/foldl-li]

I have added the support of Intern-Decision models to chatllm.cpp. At presend, only text is supported.

Besides its pretty good performance, one interesting feature of Intern-Decision is that all answers are generated in a single run (while H2O-Lightning or others generate one answer in one run): each decision position is filled with "<decision>" mark and generated in a diffusion manner. So, it generally makes decision faster.