feat(airflow): configure ClickHouse connection and update infrastructure

Update Airflow configuration to integrate with ClickHouse DWH instead of
PostgreSQL training database. Changes include:

- Switch Airflow dependencies from PostgreSQL to ClickHouse connector
- Update docker-compose to use ClickHouse connection and correct Dockerfile
- Refactor airflow/requirements.txt to include only essential packages
- Add DAGs directory for ETL pipeline orchestration
- Update documentation to reflect Airflow integration and access credentials
- Adjust service dependencies to wait for ClickHouse startup

airflow/requirements.txt

@@ -1,14 +1,11 @@
-# Optimized requirements for Airflow Docker setup
-# Only includes packages actually used in DAGs
+# Airflow requirements для ClickHouse DWH проекта
 
-# Core database connector
+# Core database connector для metadata
 psycopg2-binary==2.9.9
 
-# Data processing (used in data_processing_dag.py and file_operations_dag.py)
+# ClickHouse provider для ETL
+# Примечание: официальный провайдер deprecated, используем clickhouse-connect
+clickhouse-connect==0.8.0
+
+# Для работы с данными
 pandas==2.1.4
-
-# Data generation library (used in file_operations_dag.py)
-mimesis==15.1.0
-
-# Airflow PostgreSQL provider (used in sql_basic_dag.py and data_processing_dag.py)
-apache-airflow-providers-postgres==5.11.1