Add thread-safe (-ish) console output

components/app/inc/thread_safe_console_output.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <f4ll/console_handler.h>
+
+#include <FreeRTOS.h>
+#include <semphr.h>
+
+class thread_safe_console_output
+{
+public:
+    using size_type = f4ll::console_handler::size_type;
+    thread_safe_console_output(f4ll::console_handler &console);
+
+    void print(char const *s);
+    void flush();
+    size_type append(char const *s);
+
+private:
+    f4ll::console_handler &m_con;
+
+    SemaphoreHandle_t m_sem;
+    StaticSemaphore_t m_sem_buf;
+};