Allow project cloner image to trust custom CA cert

Proposal

When configuring Remote Development Workspaces on a self-hosted instance, the project cloner fails because git does not trust the certificate provided by the gitlab instance.

In order for this to work, we would need a way to modify the command line used by the project cloner, or at least configure git to recognise the certificate of the server (e.g. git config --global http.sslCAInfo /my/custom/ca-certs/cert.pem)