added GNSS example

Author: Rocketct

libraries/GSM/examples/GNSSClient/GNSSClient.ino

@@ -0,0 +1,34 @@
+#include <GSM.h>
+
+REDIRECT_STDOUT_TO(Serial);
+
+#include "arduino_secrets.h"
+char pin[]      = SECRET_PIN;
+char apn[]      = SECRET_APN;
+char username[] = SECRET_USERNAME;
+char pass[]     = SECRET_PASSWORD;
+
+void mycallback(char * output);
+
+void setup() {
+  Serial.begin(115200);
+  while (!Serial) {}
+  //GSM.debug(Serial);
+  Serial.println("\nStarting connection to server...");
+  GSM.begin(pin, apn, username, pass, CATNB);
+  Serial.println("\nStarting connection ...");
+
+  Serial.println("\nEnable GNSS Engine...");
+  GSM.beginGNSS(mycallback);
+  GSM.startGNSS();
+}
+
+void loop() {
+//    GSM.startGNSS();
+//    delay(10000);
+//    GSM.stopGNSS();
+}
+void mycallback(char * output)
+{
+  Serial.println(output);
+}

libraries/GSM/examples/GNSSClient/arduino_secrets.h

@@ -0,0 +1,4 @@
+#define SECRET_PIN ""
+#define SECRET_APN ""
+#define SECRET_USERNAME ""
+#define SECRET_PASSWORD ""