Changes related to DIP upload process, refs #7641

Include qtSwordPluginWorker in new jobs process:
- Add ability if qtSwordPlugin is enabled
- Use new job classes

Fixes in DIP upload process:
- Do not save target IO at the end, it was creating nested set problems, but update it in the ES index
- Register namespaces and use Xpath queries to allow namespaced and not namespaced METS versions
I think it makes sense to keep it inside the plugin tree so if the plugin is not enabled the whole thing is ignored. We could have a jobs directory inside the plugin too for organizational purposes if that makes sense to you.

The exception "Ability not defined" could maybe be extended for this particular case of plugin workers?