Function ockam_ffi::ockam_vault_secret_publickey_get

#[no_mangle]
pub extern "C" fn ockam_vault_secret_publickey_get(
    context: FfiVaultFatPointer, 
    secret: u64, 
    output_buffer: &mut u8, 
    output_buffer_size: u32, 
    output_buffer_length: &mut u32
) -> FfiOckamError

Get the public key, given a secret key, and copy it to the output buffer.