Generalize postprocessing (#15931)

* Actually send result to face registration

* Define postprocessing api and move face processing to fit

* Standardize request handling

* Standardize handling of processors

* Rename processing metrics

* Cleanup

* Standardize object end

* Update to newer formatting

* One more

* One more

frigate/postprocessing/processor_api.py

@@ -0,0 +1,52 @@
+import logging
+from abc import ABC, abstractmethod
+
+import numpy as np
+
+from frigate.config import FrigateConfig
+
+from .types import PostProcessingMetrics
+
+logger = logging.getLogger(__name__)
+
+
+class ProcessorApi(ABC):
+    @abstractmethod
+    def __init__(self, config: FrigateConfig, metrics: PostProcessingMetrics) -> None:
+        self.config = config
+        self.metrics = metrics
+        pass
+
+    @abstractmethod
+    def process_frame(self, obj_data: dict[str, any], frame: np.ndarray) -> None:
+        """Processes the frame with object data.
+        Args:
+            obj_data (dict): containing data about focused object in frame.
+            frame (ndarray): full yuv frame.
+
+        Returns:
+            None.
+        """
+        pass
+
+    @abstractmethod
+    def handle_request(self, request_data: dict[str, any]) -> dict[str, any] | None:
+        """Handle metadata requests.
+        Args:
+            request_data (dict): containing data about requested change to process.
+
+        Returns:
+            None if request was not handled, otherwise return response.
+        """
+        pass
+
+    @abstractmethod
+    def expire_object(self, object_id: str) -> None:
+        """Handle objects that are no longer detected.
+        Args:
+            object_id (str): id of object that is no longer detected.
+
+        Returns:
+            None.
+        """
+        pass