Use custom body for the export recordings endpoint (#14908)

* Use custom body for the export recordings endpoint

* Fixed usage of ExportRecordingsBody

* Updated docs to reflect changes to export endpoint

* Fix friendly name and source

* Updated openAPI spec

frigate/api/defs/request/export_recordinds_body.py

@@ -0,0 +1,20 @@
+from typing import Union
+
+from pydantic import BaseModel, Field
+from pydantic.json_schema import SkipJsonSchema
+
+from frigate.record.export import (
+    PlaybackFactorEnum,
+    PlaybackSourceEnum,
+)
+
+
+class ExportRecordingsBody(BaseModel):
+    playback: PlaybackFactorEnum = Field(
+        default=PlaybackFactorEnum.realtime, title="Playback factor"
+    )
+    source: PlaybackSourceEnum = Field(
+        default=PlaybackSourceEnum.recordings, title="Playback source"
+    )
+    name: str = Field(title="Friendly name", default=None, max_length=256)
+    image_path: Union[str, SkipJsonSchema[None]] = None