horsegen: generate scenarios since sparks use them

horsegen/scenario.go.template

@@ -0,0 +1,23 @@
+{{- define "go-scenario" -}}
+package {{ $.Region }}
+
+// Automatically generated with horsegen; DO NOT EDIT
+
+import . "git.sunturtle.xyz/zephyr/horse/horse"
+
+const (
+	{{- range $s := $.Scenarios }}
+	Scenario{{ goenum $s.Name }} ScenarioID = {{ $s.ID }} // {{ $s.Name }}
+	{{- end }}
+)
+
+var AllScenarios = map[ScenarioID]Scenario{
+	{{- range $s := $.Scenarios }}
+	Scenario{{ goenum $s.Name }}: {
+		ID: {{ $s.ID }},
+		Name: {{ printf "%q" $s.Name }},
+		Title: {{ printf "%q" $s.Title }},
+	},
+	{{- end }}
+}
+{{ end }}