Improve docker setup

- add .dockerignore to reduce build context
- add entrypoint.sh to initialize environment before user switch
- fix Celery setting deprecation warnings
- downgrade importlib-metadata for Celery compatibility
- set TZ environment variable for consistent Celery timestamps

gvamysql/mysqltasks/settings.py

@@ -25,16 +25,16 @@ def get_env_setting(setting):
 
 
 ########## CELERY CONFIGURATION
-CELERY_BROKER_URL = get_env_setting("GVAMYSQL_BROKER_URL")
-CELERY_RESULT_BACKEND = get_env_setting("GVAMYSQL_RESULTS_REDIS_URL")
-CELERY_RESULT_PERSISTENT = True
-CELERY_TASK_RESULT_EXPIRES = None
-CELERY_ROUTES = ("gvacommon.celeryrouters.GvaRouter",)
-CELERY_TIMEZONE = "Europe/Berlin"
-CELERY_ENABLE_UTC = True
-CELERY_ACCEPT_CONTENT = ["json"]
-CELERY_TASK_SERIALIZER = "json"
-CELERY_RESULT_SERIALIZER = "json"
+accept_content = ["json"]
+broker_url = get_env_setting("GVAMYSQL_BROKER_URL")
+enable_utc = True
+result_backend = get_env_setting("GVAMYSQL_RESULTS_REDIS_URL")
+result_expires = None
+result_persistent = True
+result_serializer = "json"
+task_routes = ("gvacommon.celeryrouters.GvaRouter",)
+task_serializer = "json"
+timezone = "Europe/Berlin"
 ########## END CELERY CONFIGURATION
 
 ########## GVAMYSQL CONFIGURATION