move us_population to its own schema

[noel]

No description provided.

[github-actions]

⚠️ Test Warnings Detected:

• /__w/balboa/balboa/orchestrate/dags/bad_variable_usage.py has Variable usage outside @task decorated functions at: [(12, 20)]
• /__w/balboa/balboa/orchestrate/dags/other_examples/datacoves_sample_dag.py has Variable usage outside @task decorated functions at: [(10, 7), (11, 7), (12, 7)]

[github-actions]

⚠️ Test Warnings Detected:

Tests Summary:
Total Tests: 65
Passed: 63
Failed: 2

Warnings:
- data_aware_consumer_dag in data_aware/consumer.py should have task retries >= 3 it currently has 1.
- datacoves_bluegreen_dag in other_examples/blue_green_dag.py should have task retries >= 3 it currently has 1.