Switch to Russian in Ubuntu 18.04

Links:
1) https://gangmax.me/blog/2017/10/20/setup-chinese-input-method-in-ubuntu-18-dot-04/
2) https://help.ubuntu.com/community/ibus
3) https://www.ostechnix.com/how-to-setup-multilingual-input-method-on-ubuntu/
4) https://askubuntu.com/questions/1029588/18-04-ctrlshift-to-change-language