Add route for handling Conan package uploads

This adds a route for utilizing Workhorse object storage acceleration with Conan package uploads. It is meant to mirror the behavior of the Maven route located directly above it, but with the specific endpoint for Conan uploads.

Conan upload issue: https://gitlab.com/gitlab-org/gitlab-ee/issues/13345

Main Conan issue: https://gitlab.com/gitlab-org/gitlab-ee/issues/8248