[evm] Minimalist precompile for x/bank

Desired Behavior

As a user of an EVM wallet, I should be able to:

[ ] Make an EVM call that calls "/cosmos.bank.v1beta1.MsgSend" using a given to_address, denom, and amount. The to_address can be either a bech32 or hexadecimal, similar to precompile for fungible token mappings.
[x] Method IFunToken.bankBalance: Query the balance of the coin with denomination denom for some address, returning 0 if the account does not exist. The `address can be either a bech32 or hexadecimal.
[x] Method IFunToken.whoAmI: Query the addresses for a Nibiru account. Given some address (either the Bech32 or Ethereum hex), return both hexadecimal and bech32 representation. This method isn't related to the Bank Module, however it allows future developers to easily build on top of the functionality in x/bank and programmatically grab nibi-prefixed addresses corresponding to Ethereum address types in other smart contracts.

We can add these as methods to FunToken.sol