Pagination to Account methods

[mvares]

Each method provides only an array containing their items as a result (e.g., coins, messages, and balances), and there are some comments in the code marked withto do proposing pagination for the results of these methods. My proposal is:

[{
  page: 1,
  coins: [{ ... }]
},
{
  page: 2,
  coins: [{ ... }] 
}]

Using the example above, too we could apply it to the other methods. Furthermore, maybe creating a reusable helper function would be helpful.

[arboleya]

Closing as duplicate of:

• Implement pagination on Wallet for getCoins / getBalances #302