smite-ir: add SendError and SendWarning operations and generators

[erickcestari]

Adds SendError and SendWarning operations plus a generator for each, so programs can send BOLT 1 error and warning messages and exercise the target's error handling and force-close paths. The generators use the all-zero channel_id one time in four to cover the "all channels" case.

Closes #256

[erickcestari]

At the current state of the PR, adding SendError breaks AcceptChannelOracle for LDK (I haven't tested it with other implementations yet), because LDK accepts a new open_channel with the same temporary_channel_id after the first one has been errored out.

INFO  [smite::scenarios] Scenario initialized! Executing input...
INFO  [smite::runners] Reading input from "/input.bin"
DEBUG [smite_scenarios::scenarios::ir] [14.642µs] Executing IR program (138 instructions, 1674 input bytes)
DEBUG [smite_scenarios::executor] [630.406µs] SendOpenChannel: 331 bytes
DEBUG [smite_scenarios::executor] [812.627µs] RecvAcceptChannel: waiting
DEBUG [smite_scenarios::executor] [2.305253ms] RecvAcceptChannel: received
DEBUG [smite_scenarios::executor] [2.421323ms] SendError: 36 bytes
DEBUG [smite_scenarios::executor] [2.510861ms] SendOpenChannel: 331 bytes
DEBUG [smite_scenarios::executor] [2.516255ms] RecvAcceptChannel: waiting
DEBUG [smite_scenarios::executor] [3.631017ms] RecvAcceptChannel: received
ERROR [smite::runners] Test case failed: invalid accept_channel for temporary_channel_id 33c6df673bcc970e0d07f771b2dbe842304a1bf40a4527f5a450927e0f78a817: temporary_channel_id reuse: previous negotiation has not reached funding_created