Remove connection ID environment variables in favor of simply defining them

[AetherUnbound]

Description

We currently have a pattern of defining the connection ID for an Airflow Connection via an environment variable (with a default) in addition to the environment variable for the connection itself. This creates two new configuration values for one connection ID. Below are all of the current examples:

openverse/catalog/dags/common/constants.py

Lines 32 to 36 in a5fb3ea

	POSTGRES_CONN_ID = os.getenv("OPENLEDGER_CONN_ID", "postgres_openledger_testing")
	OPENLEDGER_API_CONN_ID = os.getenv("OPENLEDGER_API_CONN_ID", "postgres_openledger_api")
	API_CONN_ID = os.getenv("API_CONN_ID", "api")
	AWS_CONN_ID = os.getenv("AWS_CONN_ID", "aws_conn_id")
	AWS_RDS_CONN_ID = os.environ.get("AWS_RDS_CONN_ID", AWS_CONN_ID)

openverse/catalog/tests/dags/common/popularity/test_sql.py

Line 17 in a5fb3ea

POSTGRES_CONN_ID = os.getenv("TEST_CONN_ID")

openverse/catalog/tests/dags/common/loader/test_sql.py

Line 26 in a5fb3ea

POSTGRES_CONN_ID = os.getenv("TEST_CONN_ID")

openverse/catalog/tests/dags/common/test_sql.py

Line 16 in a5fb3ea

POSTGRES_TEST_CONN_ID = os.getenv("TEST_CONN_ID")

These values rarely change (if ever), and do not need to be configured via environment variable.

Instead, we should define these values outright as constants and remove the environment variables from the catalog's env.template file.

[duwarakan]

What should be the target branch?

[zackkrida]

Hi @duwarakan main is the default branch for the project and a good choice for most PR targets.