Prior to this commit, p2wsh inputs from fidelity bonds resulted in
miscalculation of transaction fees, even in cases where the exact set of
inputs were known (such as a direct send).
In this commit we change the estimation to a model in which the caller
of jmbitcoin.secp256k1_transaction.estimate_tx_size must specify a list
of types, one for each input to the transaction, and the same for
outputs. In some cases, the caller of the function uses the default
script type of the wallet, but in other cases where the caller can know
the exact types of each utxo used as input, and each destination used as
output, they are specified explicitly. In particular, the use of
fidelity bond outputs as input to transactions can be accounted for.
Currently this is only done in direct send payments; coinjoins still
fall back to assuming all inputs the same type (note that it is not
possible to use fidelity bond utxos as inputs to coinjoins).
Note also that the burn destination calculation in direct send is
removed, since it is not used, so the maintenance burden is best
avoided.