gitserver: relax npm package file limits
Created by: tsenart
Background
Many packages in production fail to clone due to hitting the current file limits (max files and max size).
This PR:
- Makes us skip any files larger than the existing 15MB limit instead of hard failing the whole clone.
- Removes the maximum file limit per package. Happy to revert this commit after discussing the usefulness of enforcing this limit.
Test plan
Existing unit and integration tests should tell us this patch introduces no regression.