Refactor endpoint /program/year/month/day

Refactored remaining endpoint /program/<int:year>/<int:month>/<int:day>/ to use mixin class instead of plain function and added annotations.

Date handling tested using debug print statements - so needs further testing.

program/views.py

@@ -143,6 +143,17 @@ def gap_entry(*, gap_start: datetime, gap_end: datetime) -> dict:
     }
 
 
+@extend_schema_view(
+    create=extend_schema(summary="List schedule for a specific date."),
+    list=extend_schema(
+        summary="List schedule for a specific date.",
+        description=(
+            "Returns a list of the schedule for a specific date."
+            "Expects parameters `year` (int), `month` (int), and `day` (int) as url components."
+            "e.g. /program/2024/01/31/"
+        ),
+    ),
+)
 class APIDayScheduleViewSet(
     mixins.ListModelMixin,
     viewsets.GenericViewSet,