httpd: Validate blob size for blob end readme endpoints — heartwood

Similar to what we do on the /raw endpoint, we should also make sure that the blob end readme endpoints don’t serve too big files, who can eventually freeze the http consumer.

     let (repo, _) = ctx.repo(project)?;
     let repo = Repository::open(repo.path())?;
     let blob = repo.blob(sha, &path)?;
     let response = api::json::blob(&blob, &path);
     Ok::<_, Error>(immutable_response(response))
     if blob.size() > MAX_BODY_LIMIT {
         return Ok::<_, Error>(
             (
                 StatusCode::PAYLOAD_TOO_LARGE,
                 [(header::CACHE_CONTROL, "no-cache")],
                 Json(json!([])),
             )
                 .into_response(),
         );
     }
     Ok::<_, Error>(immutable_response(api::json::blob(&blob, &path)).into_response())
 }
 /// Get project readme.

         .chain(paths.iter().map(|p| p.to_lowercase()))
     {
         if let Ok(blob) = repo.blob(sha, &path) {
             let response = api::json::blob(&blob, &path);
             return Ok::<_, Error>(immutable_response(response));
             if blob.size() > MAX_BODY_LIMIT {
                 return Ok::<_, Error>(
                     (
                         StatusCode::PAYLOAD_TOO_LARGE,
                         [(header::CACHE_CONTROL, "no-cache")],
                         Json(json!([])),
                     )
                         .into_response(),
                 );
             }
             return Ok::<_, Error>(
                 immutable_response(api::json::blob(&blob, &path)).into_response(),
             );
         }
     }