Add player and game loop

iris_c/player.c

@@ -0,0 +1,12 @@
+#include "player.h"
+
+#include <stddef.h>
+
+player_t player_create(uint16_t x, uint16_t y) {
+    return (player_t){.x = x, .y = y};
+}
+
+void player_process_action(player_t *player, const char *action) {
+    (void)player;
+    (void)action;
+}