Add user state to search-for-staged-users output

Overview

To help customers determine which users they need to migrate i.e. are missing on the destination GitLab instance, we should add state to our search-for-staged-users.

The result would be:

[09 Jul 2020 11:44:52][INFO]|users.search_for_staged_users:370| Users found (1):
{
    "email": "alvarodecamposfp@protonmail.com",
    "id": 691,
    "state": "active"
}
[09 Jul 2020 11:44:52][INFO]|users.search_for_staged_users:372| Users NOT found (1):
{
    "4": {
        "email": "dastor+snoopy@gitlab.com",
        "state": "active"
    }
}

Tasks

• Add the user state field to new_users and users_not_found
• Update docs if needed (workflow, runbooks, README, migration metrics, etc.)

Acceptance Criteria

• search-for-staged-users outputs state for found and missing users on destination
• Existing UTs pass locally