Decouple the openwebui and the ollama. in inference-cpp-xpu dockerfile

[ACupofAir]

Description

• Following the suggestion on ipex-llm-cpp-xpu container #12364, remove the openwebui start script in ipex-llm-inference-cpp-xpu docker image.
• Change the openwebui document of inference-cpp.
• Have tested.

[jason-dai]

Need to update https://github.com/intel-analytics/ipex-llm/blob/main/README.md#docker and https://github.com/intel-analytics/ipex-llm/blob/main/README.zh-CN.md#docker too

[glorysdj]

LGTM

[ACupofAir]

Have updated document in https://github.com/intel-analytics/ipex-llm/blob/main/README.md#docker, which refer to docs/mddocs/DockerGuides/docker_cpp_xpu_quickstart.md

[jason-dai]

Have updated document in main/README.md#docker, which refer to docs/mddocs/DockerGuides/docker_cpp_xpu_quickstart.md

[ACupofAir]

Have updated document in main/README.md#docker, which refer to docs/mddocs/DockerGuides/docker_cpp_xpu_quickstart.md

I removed the OpenWebUI part of the docker image and only kept ollama; and the linked document mentions how to use OpenWebUI as the front end to connect to ollama. Now I also remove 'OpenWebUI' in the readme.md and readme.zh-CN.md.