Function indy_sys::anoncreds::indy_prover_store_credential

#[no_mangle]
pub unsafe extern "C" fn indy_prover_store_credential(
    command_handle: Handle, 
    wallet_handle: Handle, 
    cred_id: CString, 
    cred_req_metadata_json: CString, 
    cred_json: CString, 
    cred_def_json: CString, 
    rev_reg_def_json: CString, 
    cb: Option<ResponseStringCB>
) -> Error