Add saint.tech (IMG Saxony-Anhalt) image provider DAG

[wprashed]

Resolves #5571

This PR adds a new Provider API DAG for SAiNT (IMG Saxony-Anhalt) to ingest CC-licensed images of touristic points of interest, tours, and events in Saxony-Anhalt.

Changes Made

• Provider Details: Registered saint_tech as a default provider in catalog/dags/common/loader/provider_details.py and set its default image category to PHOTOGRAPH.
• API Ingester Script: Created catalog/dags/providers/provider_api_scripts/saint.py containing the SaintDataIngester class. The script handles pagination via the page and pageSize parameters, passing an API key fetched from the Airflow Variable API_KEY_SAINT. It extracts the PrimaryImage attributes (URL, width, height), POI title, foreign identifier, and evaluates the attached licenses to ensure compatibility.
• Workflows: Registered SaintDataIngester in catalog/dags/providers/provider_workflows.py to run on a monthly schedule.
• Unit Tests: Added unit tests in catalog/tests/dags/providers/provider_api_scripts/test_saint.py for fetching parameters, batch data extraction, and correct parsing of records.

Testing Instructions

1. You must set an Airflow variable for the API key to test the script:
   airflow variables set API_KEY_SAINT "<your-saint-tech-api-key>"
2. Run the unit tests locally to verify the mocked data parsing:
   just catalog/test tests/dags/providers/provider_api_scripts/test_saint.py
3. Optionally, trigger a manual test run of the saint_tech_workflow DAG to verify real-world data ingestion works as expected.