[Apps][Examples] Add pubkeyhash and privkey to the createWallet example

Summary:
T3203

Adding the public key hash and privatekey to the createWallet example output since they are frequently used in smart contract instantiations, hence would be handy for app devs.

Test Plan: npm test

Reviewers: bytesofman, #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D14363