refs #10187. Report of group processing success.

Group workspaces don't indicate via the logs that they have finished
processing. Normal execution does. I've fixed that here. I've also added a
message about the fact that group processing completion has been done so
that timings can be seen to relate to the overall processing. This will
help where the native processGroups is used, and algorithm execution logs
are reported in addition.
Merge branch 'feature/10187_process_groups' into develop