move env helpers out of the config package (#24648)

go2rtc's create_config.py imported frigate.config.env, which ran the frigate.config package init and loaded every detector plugin. Since the onnxruntime 1.30 bump, importing onnxruntime takes about 5s on some hosts, so go2rtc started after Frigate's cameras and every ffmpeg process failed to connect to the restream until it came up. The env helpers now live in frigate.util.env, so go2rtc's config script no longer imports onnxruntime.

frigate/api/camera.py

@@ -33,11 +33,11 @@ from frigate.config.camera.updater import (
     CameraConfigUpdateEnum,
     CameraConfigUpdateTopic,
 )
-from frigate.config.env import UnknownVariableError, substitute_frigate_vars
 from frigate.models import User
 from frigate.util.builtin import clean_camera_user_pass, get_record_segment_time
 from frigate.util.camera_cleanup import cleanup_camera_db, cleanup_camera_files
 from frigate.util.config import find_config_file
+from frigate.util.env import UnknownVariableError, substitute_frigate_vars
 from frigate.util.image import run_ffmpeg_snapshot
 from frigate.util.live_streams import (
     generated_transcode_streams,