Smart-escrow brought in develop's new fields and transactions, which
took the codes the contract feature used. Move the contract codes:

- transaction types 92-97 -> 103-108
- sfContractHash, sfContractID: UINT256 43, 44
- sfContractCode, sfFunctionName, sfEventName: VL 51-53
- sfContractAccount: ACCOUNT 33
- sfFunction .. sfContractEvent: OBJECT 40-44

Read the gas and code-size limits from the ledger's voted fees, as
EscrowFinish now does; ServiceRegistry::getFees() is gone.

Adapt the contract code to the merge: CamelCase type names, the new
RPC handler table, ledger entry wrappers for the contract types, the
new wasm test fixtures, and the generated host error codes. Patch the
storage test contract for the renumbered codes and regenerate
protocol_autogen.