Promote onewire, ds18b20 and ds248x to stable. (#117)

It works and it is tested.

devices/ds18b20/ds18b20.go

@@ -25,8 +25,8 @@ import (
 	"errors"
 	"time"
 
+	"periph.io/x/periph/conn/onewire"
 	"periph.io/x/periph/devices"
-	"periph.io/x/periph/experimental/conn/onewire"
 )
 
 // New returns an object that communicates over 1-wire to the DS18B20 sensor with the

devices/ds18b20/ds18b20_test.go

@@ -9,9 +9,9 @@ import (
 	"testing"
 	"time"
 
+	"periph.io/x/periph/conn/onewire"
+	"periph.io/x/periph/conn/onewire/onewiretest"
 	"periph.io/x/periph/devices"
-	"periph.io/x/periph/experimental/conn/onewire"
-	"periph.io/x/periph/experimental/conn/onewire/onewiretest"
 	"periph.io/x/periph/host"
 )
 

devices/ds248x/dev.go

@@ -10,7 +10,7 @@ import (
 	"time"
 
 	"periph.io/x/periph/conn"
-	"periph.io/x/periph/experimental/conn/onewire"
+	"periph.io/x/periph/conn/onewire"
 )
 
 // Dev is a handle to a ds248x device and it implements the onewire.Bus interface.