Issue export csv attachment

This pull request exports tasks and task_runs in CSV and JSON format as attachments, so they can be downloaded by the browser as a file. The filename will be include the name of the project, and if it's the task or task_run table for that project.

Additionally, info field (within Task or TaskRun) will be exploded (only first level) so simple projects can automatically analyzed in CSV formats.
maybe this is no longer needed