add chinese support for localpart

[LaysDragon]

Bot generate part of ulocalpart via display name..
But it will lead to some problem if display name container some non-English character some thing like

• github 通知 => github___
• github 大小 => github___
  Those different display name webhook will share same localpart because of failed generated of specified character
  there is a library can use to solve this problem like this one
  https://www.npmjs.com/package/limax

[LaysDragon]

https://github.com/LaysDragon/matrix-appservice-webhooks/tree/chinese_support
here is my implenment...It will caused duplicate bot appear due to fixed localpart if there is any webhook have been deployed