Add Support for sparse checkout

[sasinda]

🚀 Feature Proposal

Feature to sparse clone a repo in .meta projects configuration.

Motivation

Some of repos that need to be cloned into meta repo can be mono repos. In the meta repo it would be nice to be able to do a sparse checkout of such a mono repo into the meta repo.

Example

{ "projects": { "project1": "https://github.com/myorg/repo1.git/project1", ....