Add support for partial git clones (git clone --filter)

As stated on ticket BSERV-11639, our company would like to have support for partial git clones. I will paraphrase the same arguments stated for Bitbucket Server.

Problem Definition

A user needs to clone a large repository. If a user needs to work in a certain subdirectory of the repository, they are required to clone the entire repository. When a repository is large (Example: 1GB+) it can take some time to clone files that may not be required.

Suggested Solution

Since Git 2.18, Git protocol v2 has introduced the --filter flag to enable partial clones

This will allow users to clone specific subdirectories of a repository only.

Why this is important

This will increase cloning performance on large repositories.