moved files out of subdirectories, added required documentation

src/mr_goose.h

@@ -0,0 +1,12 @@
+#ifndef __MR_GOOSE_H__
+#define __MR_GOOSE_H__
+
+#include "player.h"
+
+class mr_goose final: public player_base {
+public:
+        mr_goose(RNG *rng, const feature enabled_features);
+        const char *get_race_name() const override;
+};
+
+#endif