Refactoring, housekeeping, documentation

Add a class diagram. Still needs some details.
Refactor to better respect SOLID principles.
Housekeeping, move and rename classes/files.

app/include/FanGenerator.h

@@ -0,0 +1,23 @@
+#ifndef MAPPING_H_
+#define MAPPING_H_
+
+#include <memory>
+#include <vector>
+
+#include <fan/Fan.h>
+#include <pwm/PWMControl.h>
+#include <sensor/Sensor.h>
+
+class FanGenerator {
+public:
+  std::vector<std::shared_ptr<Fan>>
+  FindFans(std::vector<std::shared_ptr<Sensor>> rpmSensors,
+           std::vector<std::shared_ptr<PWMControl>> pwmControls);
+
+private:
+  template <class Printable>
+  void print(std::string listLabel,
+             std::vector<std::shared_ptr<Printable>> list);
+};
+
+#endif // MAPPING_H_