hekate: clean unused stuff

Remove anything that will never be in TUI in the future.
Especially these that need modernization.

bootloader/config.h

@@ -44,10 +44,5 @@ typedef struct _hekate_config
 
 void set_default_configuration();
 int create_config_entry();
-void config_autoboot();
-void config_bootdelay();
-void config_backlight();
-void config_auto_hos_poweroff();
-void config_nogc();
 
 #endif /* _CONFIG_H_ */