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`)

TactilityHeadless/Include/Tactility/TactilityHeadless.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include "Tactility/hal/Configuration.h"
+
+#include <Tactility/TactilityCore.h>
+#include <Tactility/Dispatcher.h>
+
+namespace tt {
+
+/** Initialize the hardware and started the internal services. */
+void initHeadless(const hal::Configuration& config);
+
+/** Provides access to the dispatcher that runs on the main task.
+ * @warning This dispatcher is used for WiFi and might block for some time during WiFi connection.
+ * @return the dispatcher
+ */
+Dispatcher& getMainDispatcher();
+
+} // namespace
+
+namespace tt::hal {
+
+/** While technically this configuration is nullable, it's never null after initHeadless() is called. */
+const Configuration* _Nullable getConfiguration();
+
+} // namespace