See the commits. There is not much to write to the most of the commits, because it's just "replace this for that". Lame messages are worse than no messages, especially with self-explanatory summary. I hope. I'm fine to extend the texts, if needed.
I'd ideally drop also the
GS_PLUGIN_ACTION_... actions, but those are used for other things (like in the shell, to fine tune error messages).
I know the repo operations did call refine, or it seems so from the plugin code, but I think it's not needed.
GsPluginJobManageRepository - I do not like code duplication, thus I chose this approach, instead of adding four same structures doing the same job.