New "user matching mode" option for existing user with the same path only

**Is your feature request related to a problem? Please describe.**
Hi, i would like to pre-populate new users with group information, attributes, etc so that when the new user actually login from the expected IdP, they automatically get assigned to groups and inherit the attributes. This can already be done with existing "link to user with identical username|email", but it poses security issues as it can be used to login to existing users even the one that comes from different IdP. I think, if there is a limit to which existing user can be linked to, then this security issues might be minimized, e.g. only allow linking to existing user if they are created on the same path where new user from related IdP will be created

**Describe the solution you'd like**
Add new options to user matching mode
- Link to a user with identical username at the same path, but deny enrollment when the username already exists in other path

**Describe alternatives you've considered**
Add attribute to the current user object to specify whether it can be linked with the same username from the specific IdP

**Additional context**
-