Add Kerberos authentication support to SCCM mixin

[erdragone430]

Description

This change adds support for Windows Authentication (Kerberos and NTLM) to the SCCM mixin.

Previously, the mixin methods register_request and get_secret_policies did not pass the preferred_auth option to send_request_raw. This caused SCCM modules to ignore the user-defined HTTP::Auth setting.

I've updated the opts hash in the SCCM mixin to explicitly include preferred_auth sourced from the datastore. This allows modules like get_naa_credentials to work in environments requiring GSSAPI negotiation.

Verification

List the steps needed to make sure this thing works:

• Start msfconsole
• use auxiliary/admin/sccm/get_naa_credentials
• set HTTP::Auth kerberos
• set HttpTrace true
• run
• Verify that the HTTP request is directed to /ccm_system_windowsauth/request. (The _windowsauth suffix confirms the mixin is now correctly passing the authentication requirement).
• Verify that the multipart message body remains correctly formatted when the new options are passed.

Documentation

No new documentation is required as this uses existing HttpClient options.