Add helper for asserts and block info

[friedger]

How to assert a tx result?

Also a helper for current user nonce, and current reward cycle

[friedger]

For tx results, use:

let [block, tx] = await waitForStacksTransaction(
      orchestrator,
      response.txid
    );
    expect(tx.result).toBe("(ok true)");

No need for user nonces for now.

For current reward cycle, call getPoxInfo and see info.current_cycle.id