add persistent flag --kind

use it to configure the client

internal/xair/kinds.go

@@ -0,0 +1,19 @@
+package xair
+
+type MixerKind string
+
+const (
+	KindXAir MixerKind = "xair"
+	KindX32  MixerKind = "x32"
+)
+
+func NewMixerKind(kind string) MixerKind {
+	switch kind {
+	case "xair":
+		return KindXAir
+	case "x32":
+		return KindX32
+	default:
+		return KindXAir
+	}
+}