Import a batch job by the program its step runs

A JCL job used to be turned away on its type alone, so a batch job could never be imported however much source it carried. It is now judged on content: the job's steps are read, and the first step naming a program the export has source for becomes the operation's entry program — which is how a JCL-rooted operation works, since it names its program in a step rather than in the job itself.

A job with nothing to convert says what it actually runs instead of reporting that JCL is unsupported, and points out that the programs such a job compiles or defines import as their own operations.

Importing several operations at once is now best-effort: each is imported independently and reports its own outcome, so one failure no longer discards the operations already brought in, and a batch mixing a job with real programs still imports the programs.