Issue #3623952: Answer a conflict from the command line

drush myrest:resolve names a file a generation left for a person - by its file name or the ID of its endpoint - and gives it exactly one answer: --take-generated, --keep-mine, --unfreeze or --subclass --module=. It asks nothing, so it runs in a deployment: taking the generated version prints the edit it loses before it writes, and the subclass answer prints the class to create and the change to move into it and writes nothing. It exits with 0 when the file was answered and with 1 when there was nothing to answer or the answer could not be carried out. Finding the file, choosing the answer and every word printed are in MyrestResolveReport, tested without drush; the generation report names the command instead of pointing at the README.

Closes #3623952