Function install_cfpack 

pub async fn install_cfpack(
    pack_path: &Path,
    instance_name: &str,
    base_dir: &Path,
    java_path: Option<&Path>,
    curseforge: &CurseForgeClient,
    progress: ProgressFn,
) -> Result<ModpackInstallResult>

Install a CurseForge modpack into instance/{instance_name}. Only required files are downloaded.