Add ipex extra in pyproject.toml to use restricted transformers version

[jiafuzha]

IPEX has restriction on transformers version, but llm-on-ray doesn't have. To verify IPEX and other llm-on-ray functions in parallel in CI, we can add a new ipex extra in pyproject.toml with right transformers version. Then, add corresponding nightly CI in github workflow.

The brief steps are,

1. add "ipex" extra
   cpu = [
   "transformers>=4.35.0", # some models need higher version of transformers
   "intel_extension_for_pytorch==2.1.0+cpu",
   "torch==2.1.0+cpu",
   "oneccl_bind_pt==2.1.0+cpu"
   ]
   **+ipex = [

• "transformers==4.31.0", # to make fully functional ipex. choose right version based on following ipex version.
• "intel_extension_for_pytorch==2.1.0+cpu",
• "torch==2.1.0+cpu",
• "oneccl_bind_pt==2.1.0+cpu"
  +]**

2. add a separate dockerfile so that it can be cached properly in CI build.
   copy one of Dockerfiles under dev/docker and rename it to Dockerfile.ipex. After that, replace 'pip install ...' with 'pip install .[ipex]

3. add nightly CI
   copy the workflow-inference.yaml and rename to workflow-inference-ipex.yaml and call workflow-inference-ipex.yaml to workflow_orders_nightly.yaml.
   call-inference:
   uses: ./.github/workflows/workflow_inference.yml
   with:
   ci_type: nightly

• call-inference-ipex:
• uses: ./.github/workflows/workflow_inference-ipex.yml

Inside workflow-inference-ipex.yaml, add inference tests for ipex supported models.

[KepingYan]

As a reminder, since mpt-7b CI failed, set ipex configuration to False in #125 first after verification.