Add quiet open and close support for curtain

First and foremost, thanks for this! I really appreciate it. 


I'm not sure if this is the right place but I'd love if this have a command to quietly open and close the curtain. Currently I use home assistant to do so but it only uses turn_on and turn_off to open/close. 

Docs: 
https://github.com/OpenWonderLabs/SwitchBotAPI/blob/main/README.md#curtain-3-2