Expose worker undo as a host function

[vigoo]

The final step of the worker undo feature after #1180 and #1181 is to expose the same functionality for Golem workers via a new Golem-specific host function.

Steps:

• Define the new API in golem:api/[email protected] in golem-wit
• Implement it in worker executor by using the WorkerProxy to direct the request back through worker service (this is necessary because the target worker may not live in the same executor).
• Optionally this can be optimized to directly call undo if the worker is local (like in the RPC implementation)
• The implementation must be durable (write to the oplog) so the undo is not performed again during replay. See for example how "hot update" is exposed to workers, which is very similar.
• Create a worker exeuctor test where a worker is undoing another worker through the host function