Memory tracking files related to query processing were recently moved to the db/memory_tracking subdirectory. We should update the owners yml file to ensure that the proper stakeholders get notified for code changes.

• For the memory_usage_tracker, we will assign this to query-execution because it is used to figure out when to spill queries to disk.
• Because this project falls into the observability category and we created some new files for this project, I'm thinking that we make those new files assigned to qi-observability