Xiaomi Cameras - multiple models (#14244)

* Added support for Xiaofang Camera

* Added entry for Xiaofang 1080p camera

* Code fix

* Minor comment fix

* Updated coveragerc for Xiaomi cameras

* Added Xiaomi Camera

Added Xiaomi Camera to accommodate multiple models like Yi, Xiaofang, etc.

* Minor code fix

* Minor code fix

* Added model property

* Update xiaomi.py

* Minor code fix

* Update xiaomi.py

* Update xiaomi.py

* Minor code fix

* Package requirement fix due to Version conflict

* To fix conflicts

* Update package_constraints.txt

* Minor fix

* Update xiaomi.py

* Update xiaomi.py

Changes made per comment

* Update xiaomi.py

* Don't update on add.