feat(api): add lfs metadata

[McPatate]

Full lfs object looks like this :

"lfs": {
    "sha256": "5b1da7ebe3bdcc58c91eb9916f7d881791ac2659307f0c383c325361382f2f42",
    "size": 2239866697,
    "pointerSize": 135
}

Needed for the repo scanner

[Narsil]

Can we add a test for it ? (Also so I can have a look at what models return that could be interesting in other places to get file sizes without Range:0-0.

[Narsil]

Quite nice.

I propose a different (simpler imho) internals.

Otherwise looks good. Not sure how cargo fmt didn't pick up those before.

[Narsil]

How were we getting away without it before, is it the map(Box?) ?

[McPatate]

Response::into_json returns an io::Result<T> while serde_json::from_value returns a Result<T, serde_json::Error>

[McPatate]

And reqwest::Response::json returns a Result<T, reqwest::Error>

[Narsil]

LGTM