adding a generic CANalyst-II backend

Hi, guys.

Version 3.x of python-can worked well with my CANalyst-II. However, in version 4.x, I found that the backend of python-can for CANalyst-II has changed. My CANalyst-II can not work with python-can.

* As far as I know, the genuine CANalyst-II is manufactured by [ZLG](https://www.zlg.com/), but there are many cloned CANalyst-II devices on the market, whose manufacturers provide ZLG-compatible DLLs.

* Version 3.x of python-can can support CANalyst-II of different manufacturers by simply replacing the DLL.
* Version 4.x of python-can may only support CANalyst-II devices from Chuangxin Technology.

Would you consider adding a 'generic' CANalyst-II backend like the 3.x version?