Add simple hello world application

src/app/hello/main.cc

@@ -0,0 +1,6 @@
+#include <base/component.h>
+
+void Component::construct(Genode::Env &env)
+{
+  Genode::log("Hello World!");
+}

src/app/hello/target.mk

@@ -0,0 +1,3 @@
+TARGET = hello
+SRC_CC = main.cc
+LIBS   = base