Enable LFS chunked encoding

LFS currently doesn't use chunked transfers, which causes the whole body to be read before it is stored. This causes 5+ GB uploads to be blocked by Cloudflare on GitLab.com.

The LFS client will only enable this mode if the server sends the Transfer-Encoding: chunked HTTP header.

This is guarded by the lfs_chunked_encoding feature flag to ensure this mode doesn't cause issues.

Relates to #285489 (closed)

Testing

Using gitlab-development-kit!1693 (merged), tcpdump, and Wireshark, I was able to verify that this flag caused the client to send the payload via HTTP chunked transfers.

Before

After