Add admin user authentication pathway for deployed environment

[qcjames53]

Certain actions taken on a running Foreman server require authenticated API access, which foremanctl currently cannot access when a user changes the default admin username and password.

Acceptance Criteria

• When deploying Foreman, build a 'foremanctl' admin user which can authenticate with the server through a protected secret key.
• Follow best practices for protecting the key.
• Update all existing post-deploy database queries to use authenticated API calls. Feature gate where needed.
• If a required API does not exist on the Foreman side, use best judgement. Request a new API endpoint from the Foreman project and document unmigrated queries with source comments + new foremanctl issues.