A few fixes and some improvements preparing for more to come

fixes

• detection of MQTT availability since HA core 2022.9.X (#225)
• refined cloud key retrieve to try fix some issues (#231 and #186)
• attempt to get the updated ip address from DHCP (#229) (not really tested - very experimental)
• use device native position in covers with newer firmwares (#227) (not really tested - hope for the best!)