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

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

pkg/tts/piper.go

@@ -0,0 +1,20 @@
+package tts
+
+import "os"
+
+type Piper struct {
+	assetDir string
+}
+
+func New(assetDir string) (*Piper, error) {
+	if _, err := os.Stat(assetDir); err != nil {
+		return nil, err
+	}
+	return &Piper{
+		assetDir: assetDir,
+	}, nil
+}
+
+func (s *Piper) TTS(text, model, dst string) error {
+	return tts(text, model, s.assetDir, "", dst)
+}