Add semaphore based signal implementation

include/sta/os2/signal.hpp

@@ -0,0 +1,27 @@
+#ifndef STA_OS2_SIGNAL_HPP
+#define STA_OS2_SIGNAL_HPP
+
+#include <sta/signal.hpp>
+
+#include <cmsis_os2.h>
+
+
+namespace sta
+{
+	class Os2Signal : public Signal
+	{
+	public:
+		Os2Signal(osSemaphoreId_t * semaphore);
+
+		void notify() override;
+		bool peek() override;
+		bool test() override;
+		void wait() override;
+
+	private:
+		osSemaphoreId_t * semaphore_;
+	};
+} // namespace sta
+
+
+#endif // STA_OS2_SIGNAL_HPP