cpu/esp: set esptool as supported programmer
cpu/esp: set esptool as supported programmer

OTAkeys/RIOT,OlegHahm/RIOT,jasonatran/RIOT,jasonatran/RIOT,OlegHahm/RIOT,authmillenon/RIOT,kYc0o/RIOT,jasonatran/RIOT,miri64/RIOT,kaspar030/RIOT,OlegHahm/RIOT,kaspar030/RIOT,authmillenon/RIOT,ant9000/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,kYc0o/RIOT,jasonatran/RIOT,OTAkeys/RIOT,ant9000/RIOT,kaspar030/RIOT,ant9000/RIOT,kYc0o/RIOT,OTAkeys/RIOT,jasonatran/RIOT,miri64/RIOT,authmillenon/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,ant9000/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,authmillenon/RIOT,OlegHahm/RIOT,kaspar030/RIOT,miri64/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,authmillenon/RIOT,kYc0o/RIOT,miri64/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,ant9000/RIOT,miri64/RIOT