Support Git Filters on Clone

Workaround

None currently. This is causing our preparing step to take ~2 minutes on average

Problem

We manage our Terraform configurations in a large monorepo. While Spacelift already performs shallow clones and supports sparse-checkout, the initial git clone operation remains a performance bottleneck for our workflows. We've observed that the preparing phase of our Spacelift runs is considerably slower than our local Terraform apply processes. The primary reason for this is the absence of support for advanced Git filters, such as --filter=blob:none. Locally, we leverage this filter to avoid downloading file contents (blobs) during the clone, which drastically reduces clone times from several minutes to mere seconds. Integrating this filtering capability into Spacelift would directly address this performance deficit, making our IaC deployment pipeline much more efficient. As our repository's size increases, the impact of this missing feature will only get worse.