Tiup set Root Password during deployment

[qqqdan]

Feature Request

Is your feature request related to a problem? Please describe:

Describe the feature you'd like:

Currently, TiDB will create a root user with no password and bind to 0.0.0.0/::. This is a potential security issue if users do not have a firewall configured correctly, or if a rogue actor has local access.
TiDB need support to set the password for root user.

Why the featue is needed:

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy: