feat: Engines API endpoints should be consistent

[gabrielle-ong]

Problem Statement

Standardize Engines APIs to have query params in the body

Feature Idea

1. Installation / Uninstall: engines/install
2. Get / Set Default: engines/default
3. Load / Unload: engines/load
4. Update engines/update

[gabrielle-ong]

@namchuai Qn:
5. Get Engine: does it remain GET /engine/NAME (like GET Models/ID)?

• and how does this work with versions, variants?
• Currently we allow GET /engines/{engine_type}/{version}

[namchuai]

@gabrielle-ong ,

5. Get Engine: does it remain GET /engine/NAME (like GET Models/ID)?

Yes, API below will list all installed llamacpp engines. Currently we don't have GET /{version} because actually there's not much data for a version.

curl --location 'http://127.0.0.1:3928/v1/engines/llama-cpp'

[
    {
        "engine": "llama-cpp",
        "name": "mac-arm64",
        "version": "v0.1.39"
    }
]

[gabrielle-ong]

Thanks @namchuai! Marking as complete and pending #1675 from me