Add support for ZhongHong HVAC Controllers (#14552)

* first blood for ZhongHong HVAC Controller

* add requirements

* requirements_all.txt updated

* add zhong_hong.py to coveragerc

* add comments

* unique_id add platform name

* zhong_hong_hvac version bump to 1.0.1

* improve some coding style to match the project standard

* zhong_hong_hvac version bump to 1.0.4

* zhong_hong_hvac version require 1.0.7

* update requirements by script/gen_requirements_all.py

* zhong_hong_hvac version bump to 1.0.8

* fix startup problem

* remove unused import

* zhong_hong_hvac version bump to 1.0.9

- operation_mode: cold -> cool

* start hub listen event when all climate entities is ready

* use dispatcher to setup hub

* var name change

SIGNAL_DEVICE_SETTED_UP -> SIGNAL_DEVICE_ADDED

* async problem fix

* bugfix: set_operation_mode forget to use upper case

* stringify the exception instead of print full stack of traceback

* avoid to call str(exception) explicity

* remove unnecessary try...except clause

* remove unused import