Small change: explain the use of keys in JS documentation about iroha-2-docs

[6r1d]

I could add another issue for this code, but I feel those topics are intertwined.

import { cryptoTypes } from '@iroha2/crypto-core'
import { Signer } from '@iroha2/client'
import { AccountId, DomainId } from '@iroha2/data-model'

// Key pair from previous step
declare const keyPair: cryptoTypes.KeyPair

const accountId = AccountId({
  // Account name
  name: 'alice',
  // The domain where this account is registered
  domain_id: DomainId({
    name: 'wonderland',
  }),
})

const signer = new Signer(accountId, keyPair)

Denis Kitaev also requested this information to be added to the JS SDK docs:

• Where does the alice account name come from?
• Is alice pre-set in the container peers?
• What about the wonderland domain?
• What about the key pair?

[kidys]

Yes it would be great if the documentation would explain step by step what to do... how to make requests from Node.js/JavaScript environment... Exactly step by step...