settings: introduce settings YAML file to complement cmd arguments

lib/settings/strings.go

@@ -0,0 +1,24 @@
+package settings
+
+import "maps"
+
+type Strings map[string]string
+
+var DefaultStrings = make(Strings).set(map[string]string{
+	"challenge_are_you_bot": "Checking you are not a bot",
+	"error":                 "Oh no!",
+})
+
+func (s Strings) set(v map[string]string) Strings {
+	maps.Copy(s, v)
+	return s
+}
+
+func (s Strings) Get(value string) string {
+	v, ok := (s)[value]
+	if !ok {
+		// fallback
+		return "string:" + value
+	}
+	return v
+}