Move pd-event-logger to Runway

https://gitlab.com/gitlab-com/gl-infra/pd-event-logger is the only service remaining in gitlab-infra-automation and is a good candidate to move to Runway.

Tasks

• Create inventory entry in Runway https://gitlab.com/gitlab-com/gl-infra/platform/runway/provisioner/-/merge_requests/271
• Update secrets #25547 (comment 1973573385)
• Create CI config and update project readme: pd-event-logger!10 (merged)
• Remove old cloudrun
• Update webhook in PD
• Setup monitoring gitlab-com/runbooks!7584 (merged)
• Validate PD events