improve gexit with init function and add basic mlx image gestion

srcs/draw/draw.c

@@ -0,0 +1,15 @@
+#include "cube3d.h"
+
+static void	draw_pixel(t_game *game, int x, int y, int color)
+{
+	unsigned int	position;
+
+	position = y * game->sizel + x * (game->bpp / 8);
+	*(unsigned int*)(game->img_data + position) = color;
+}
+
+void	draw(t_game *game)
+{
+	draw_pixel(game, game->plr_x, game->plr_y, 0x00FF0000);
+	mlx_put_image_to_window(game->mlx_ptr, game->win_ptr, game->img_ptr, 0, 0);
+}