Create test data generator

In order to create the stats API and view we need a test database with a lot of values. To have that, we need some sample data generator code in Python. For example something that spawns 100 threads with each having their unique simulated device_id and then submitting data 20 times so that the passing of global time is mocked and each measurement is at least 12 hours apart.

Research if Flask or SQLAlchemy has some fixture code that can already generate this, or write a custom tool for it.