chore: move the go code into a subfolder

apps/api/internal/migration/delete_parent_counts_trigger.sql

@@ -0,0 +1,13 @@
+{{ define "delete_parent_counts_trigger" -}}
+
+CREATE OR REPLACE TRIGGER delete_parent_counts_trigger
+    AFTER DELETE
+    ON {{ .Table }}
+    FOR EACH ROW
+    EXECUTE FUNCTION projections.delete_parent_counts(
+        '{{ .ParentType }}', 
+        '{{ .InstanceIDColumn }}', 
+        '{{ .ParentIDColumn }}'
+    );
+
+{{- end -}}