Feature Request: Mapping model name to LoRA config

[ngxson]

Prerequisites

• [X] I am running the latest code. Mention the version if possible as well.
• [X] I carefully followed the README.md.
• [X] I searched using keywords relevant to my issue to make sure that I am creating a new issue that is not already open (or closed).
• [X] I reviewed the Discussions, and have a new and useful enhancement to share.

Feature Description

I came across this idea while working on #10994

The idea is that we can maintain a list of model name mapped to LoRA config, for example:

{
    "llama-base":               [{"id": 0, "scale": 0.0}, {"id": 1, "scale": 0.0}],
    "llama-story":              [{"id": 0, "scale": 1.0}, {"id": 1, "scale": 0.0}],
    "llama-abliteration":       [{"id": 0, "scale": 0.0}, {"id": 1, "scale": 1.0}],
    "llama-story-abliteration": [{"id": 0, "scale": 0.5}, {"id": 1, "scale": 0.5}]
}

Then, user can switch the model by specifying model in the request, for example:

# first user:
{
    "model": "llama-story-abliteration",
    "messages": [
        {"role": "user", "content": "Write a NSFW story"}
    ]
}

# second user:
{
    "model": "llama-base",
    "messages": [
        {"role": "user", "content": "Is this NSFW?"}
    ]
}

Motivation

N/A

Possible Implementation

No response