[Execution Engine] Verify mercure progress updates logic

[markus-moser]

At the moment we have a lot of different approaches depending on the job how the progress is tracked.

• Some are based on progress percent
• Sometimes we have steps for each single element and the steps are then somehow the progress (e.g. step 3/18) -> we try to calculate a percentage out of those steps in the frontend (so .e.g 3/18 -> 17%)
• Sometimes we use the steps but also execute multiple items in one step (so each step has a normal progress in percent and we have e.g. 2 steps)
• Sometimes we have sub job run ids which start after the original job has finished (e.g. paste recursive + updating references)

Therefore we should work on the following topics:

• We need to find out if there is room for improvement in this progress calculation / step handling on backend side.
• We should somehow document for each job variant how the progress handling is done on backend side to be able to use the right approach on frontend side.

[github-actions]

Thanks a lot for reporting the issue. We did not consider the issue as "Pimcore:Priority", "Pimcore:ToDo" or "Pimcore:Backlog", so we're not going to work on that anytime soon. Please create a pull request to fix the issue if this is a bug report. We'll then review it as quickly as possible. If you're interested in contributing a feature, please contact us first here before creating a pull request. We'll then decide whether we'd accept it or not. Thanks for your understanding.