Project restructuring (fixes macOS builds) (#198)

- Create `Include/` folder for all main projects
- Fix some issues here and there (found while moving things)
- All includes are now in `Tactility/` subfolder and must be included with that prefix. This fixes issues with clashing POSIX headers (e.g. `<semaphore.h>` versus Tactility's `Semaphore.h`)

TactilityCore/Include/Tactility/kernel/critical/Critical.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <cstdint>
+
+namespace tt::kernel::critical {
+
+struct CriticalInfo {
+    uint32_t isrm;
+    bool fromIsr;
+    bool kernelRunning;
+};
+
+/** Enter a critical section
+ * @return info on the status
+ */
+CriticalInfo enter();
+
+/**
+ * Exit a critical section
+ * @param[in] info the info from when the critical section was started
+ */
+void exit(CriticalInfo info);
+
+} // namespace