feat: add tts with go-piper (#649)

Signed-off-by: mudler <mudler@localai.io>

pkg/tts/generate_unsupported.go

@@ -0,0 +1,10 @@
+//go:build !tts
+// +build !tts
+
+package tts
+
+import "fmt"
+
+func tts(text, model, assetDir, arLib, dst string) error {
+	return fmt.Errorf("this version of LocalAI was built without the tts tag")
+}