Integration of Fast-LLM

[bigximik]

Fast-LLM Integration (Draft)

This is a basic integration of Fast-LLM and is a work in progress:

• Based on the existing HFLM integration.
• The HFLM constructor is incompatible, so all components are initialized explicitly in our constructor.
• Tests are adapted from sglang since neither sglang nor our implementation supports "EleutherAI/pythia-70m"; we use Qwen2 instead. However, the test coverage is not yet as complete as in the HF integration tests.
• Quantized models will not supported in this iteration.
• Cache will not be supported in this iteration.

Still to be done:

• Integration of distributed inference.
• A test case for passing an instantiated Fast-LLM model?

Notes:

• Currently works with this branch of the Fast-LLM only: Sandbox for Implementation of generate and integration of lm_eval (evaluation harness) Fast-LLM#222