feat: Added systemShell gradle task

Author: divyanshupundir

examples/java-client/build.gradle

@@ -45,6 +45,11 @@ task listPhotos(dependsOn: 'classes', type: JavaExec) {
     classpath = sourceSets.main.runtimeClasspath
 }
 
+task systemShell(dependsOn: 'classes', type: JavaExec) {
+    main = "io.mavsdk.example.SystemShell"
+    classpath = sourceSets.main.runtimeClasspath
+}
+
 task checkstyle(type: Checkstyle) {
     configFile = rootProject.file("config/checkstyle/checkstyle.xml")
     source 'src'