Function initialize_signed 

pub fn initialize_signed(
    name: &str,
    registry: &Path,
    identity: &Path,
    root_key: &[u8],
    policy: &str,
    signature: &str,
) -> Result<InitializedTap, String>

Writes an already signed initial policy. This is public for embedders that use a signer API rather than the HARA_SIGNER command protocol.