Add audit event for ElasticDeleteProjectWorker

Note: This issue was replaced by Add a way to temporary store logs for projects deleted out of the Elasticsearch index for several months

Proposal

The kibana logs only go back 7 days which isn't long enough to debug complex index integrity issues. I propose to add an Audit Event every time the ElasticDeleteProjectWorker run with info about where it was initiated from and what project it was run for. This will help us by keeping a better log of when projects/associated data are queued for deletion from the index.