[feat] - concurrent diff processing

[ahrav]

Description:

Process diffs concurrently with workers. If we are concerned with concurrency for git sources that are operating on multiple sources (ie multiple repos, when the git objet is configured we can manually set the concurrency to 1), this would allow us to get concurrent diff processing for singular repos, and concurrent diff processing for multiple repos if we want.

Before:

After:

Checklist:

• [ ] Tests passing (make test-community)?
• [ ] Lint passing (make lint this requires golangci-lint)?