deletion of artefacts after apply is successful (configurable)

[motatoes]

Requested by M.S.

currently when configuring plan artefacts on any target including s3 digger does not delete the artefacts after the apply is completed which would lead to alot of pr plan files lingering in the bucket after the PR is merged. We can perform cleanup of plan artefacts either on successful apply within the same job or as a seperate cleanup job after the PR is merged