Revert "Add code sharing sample (#1444)" (#1464)

This reverts commit fc6222ebc8.

code_sharing/client/linux/main.cc

@@ -1,6 +0,0 @@
-#include "my_application.h"
-
-int main(int argc, char** argv) {
-  g_autoptr(MyApplication) app = my_application_new();
-  return g_application_run(G_APPLICATION(app), argc, argv);
-}