"Import project from repo by URL" doc need update and more instructions

The doc "Import project from repo by URL" need update and more instructions. for now version 12.1.4, the gitpab page actual changed, but the doc is still old. and the page of 12.1.4, added two inputs, username(Optional), password(Optional), but without any placeholder or descrptions to say what username and passworld should be. So i guess it was the source git username and password, but it's failed when i used like: Git repository URL: http://ip:port/group/repo.git, Username: username, Password: password. and when i change the url to http://username:password@ip:port/group/repo.git, and clear Username and Password input, import successed.

Problem to solve

update doc and add more instructions