Automatic merge from submit-queue (batch tested with PRs 49871, 49422, 49092, 49858, 48999)

Refactor logging e2e tests, add new checks

I split existing code into smaller files to simplify the review and future changes

Also, there are new tests for stackdriver logging:
- ingesting system logs from all nodes
- ingesting logs in json format
- ingesting logs in glog format