Rework `getWalletCollateral` to support KeyWallet

[jy14898]

As part of #437, balanceTx handles adding wallet collateral in an ad-hoc fashion for each wallet. We could investigate modifying QueryM.getWalletCollateral to handle those cases by adding the parameters needed by KeyWallet's selectCollateral to it. Alternatively, we make getWalletCollateral clear that it's for CIP30 wallets.

Actually, I noticed in CIP30 that it specifies the getCollateral function should take an amount parameter, which would be useful for selectCollateral in KeyWallet too. However, it's hard to tell how one can calculate the required collateral before balancing

[klntsky]

I have two ideas:

• We may use a separate type here, something like CollateralizedKeyWallet, with a smart constructor consisting of sending a collateral Tx. But the problem is that the wallet must be provided before Contract is interpreted, but sending a Tx is a Contract action. FAIL
• We can delegate creation of KeyWallets to PlutipM monad interpreter. It can just request one extra UTXO from plutip-server on initialization and provide a pre-funded KeyWallet with collateral already set.

[ngua]

Closed by #860