feat(api): split api into multiple apps (#1626)

Fixes #1622

- split the api into 4 apps: core, history, schedule, storage
- exploded the settings into testing/prod

api/libretime_api/core/serializers/preference.py

@@ -0,0 +1,15 @@
+from rest_framework import serializers
+
+from ..models import Preference, StreamSetting
+
+
+class PreferenceSerializer(serializers.HyperlinkedModelSerializer):
+    class Meta:
+        model = Preference
+        fields = "__all__"
+
+
+class StreamSettingSerializer(serializers.HyperlinkedModelSerializer):
+    class Meta:
+        model = StreamSetting
+        fields = "__all__"