Add `coder user edit-role` command for editing user roles in CLI

[matifali]

Promoting a user to an owner role or changing user roles in a CLI context is possible only via coder organizations members edit-roles <username | user_id> [roles...]. However, this command is specific to the "organizations" structure, which is only available to Premium users. This limits OSS and single-organization deployments where role changes may still be needed.

Suggested Solution

Implement an alias for coder organizations members edit-roles to provide coder user edit-role to perform role updates for single org and OSS deployments.