input_common, common: Add a few functions

These functions include reloading udp client, testing communication and configuring calibration. I also added a function to common/thread.h to use WaitFor.

src/input_common/main.cpp

@@ -76,6 +76,11 @@ std::string GenerateAnalogParamFromKeys(int key_up, int key_down, int key_left,
     return circle_pad_param.Serialize();
 }
 
+void ReloadInputDevices() {
+    if (udp)
+        udp->ReloadUDPClient();
+}
+
 namespace Polling {
 
 std::vector<std::unique_ptr<DevicePoller>> GetPollers(DeviceType type) {