Improve messages about publishing/published projects

[cyplas]

If a project has been published and has results, it doesn't seem to be possible to delete task runs, tasks or the project itself, neither through the web interface nor through the REST API. But the web interface suggests otherwise, since it has a button "Delete all Tasks and Task Runs" along with a message "If you delete all the tasks and task runs they will be gone forever!" (although particularly attentive users may notice that the feedback post-deletion says "TASKS AND TASKRUNS WITH NO ASSOCIATED RESULTS HAVE BEEN DELETED"). With the help of Daniel's pointers, I was able to solve this directly through the database (updating the published flag and deleting the project's results). But it would be good if this was facilitated (maybe with an optional "force=1" parameter in the REST API) or documented somewhere and/or a better warning was given of what you can't do after publishing a project.

[teleyinex]

Yes, we should improve this asap.