add Sayma LED blinker example

artiq/examples/sayma/repository/blink_led.py

@@ -0,0 +1,14 @@
+from artiq.experiment import *
+
+
+class BlinkSaymaLED(EnvExperiment):
+    def build(self):
+        self.setattr_device("core")
+        self.setattr_device("led0")
+
+    @kernel
+    def run(self):
+        self.core.reset()
+        while True:
+            self.led0.pulse(100*ms)
+            delay(100*ms)