Corpus delete tasks artifacts

closes #1732 (closed)

changed milestone to %Arkindex 1.6.1

requested review from @erouchet

assigned to @mlbonhomme

added 3 commits

• df819d15...c76fdeeb - 2 commits from branch master
• dad77a88 - Delete task artifacts before deleting processes in corpus delete

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added 2 commits

• 412ff37d - 1 commit from branch master
• e9cf2e6a - Delete task artifacts before deleting processes in corpus delete

Compare with previous version

merged