This migrates the get_balance* calls to balance* to be more inline
with standard ruby method naming, i.e. the method name should reflect
what is being returned v.s. what the method is doing.

This removes the reference to the unused FaucetLimitReached error
and updates docs to refer to the correct FaucetLimitReachedError

This enables you to import a wallet with the export data directly.

This migrates the balance map parsing off of the top-level Coinbase
class and onto the Coinbase::BalanceMap class as a class method.

This also exposes a `Coinbase::Balance` object for simple parsing
of Coinbase::Client::Balances.

This makes it so that our fetches of the resource ID doesn't stutter
with the class name.

```ruby
wallet = Wallet.import(...)
puts wallet.id
```

This consolidates the transforms around assets and balances to
their respective classes, and moves them out of wallet and address.

This also adds testing and fixes the handling for fetching balances
of `weth` using `get_address_balance` and `get_wallet_balance` which
was not handled properly.

The `list_address_balances` and `list_wallet_balances` handling properly
handled `weth`.

This makes it so that we return address.transfers instead of
address.list_transfer_ids.

This updates all model's fields and adds specs that test the
inspect function to ensure we're evaluating those functions in
test.