Include basic lost and found functionalities

[ShaohongZ]

Overview

Include basic functionalities for lost and found

Changes

1. A background process to continuously store and update sightings of objects of interest in a database;
2. A simple action to find the last sighting of an object of interest.

[openminddev]

We store the data in sql, so it is a very good way for us to provide this service as the cloud service.

[openminddev]

We should not run the YOLO detector in the threading, it can block others. We need a separate instance that runs the YOLO inference that other programs can interact with.