Authentication / Radius - Add MSCHAPv2 support

[AdSchellevis]

Important notices

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• I have read the contributing guide lines at https://github.com/opnsense/core/blob/master/CONTRIBUTING.md
• I am convinced that my issue is new after having checked both open and closed issues at https://github.com/opnsense/core/issues?q=is%3Aissue

Is your feature request related to a problem? Please describe.

Currently our RADIUS authentication only offers PAP authentication, while some setups require challenge/response type authentication. With some small modifications to CHAP.php (opnsense/ports@818fa8e) we are able to implement challenge response support for our RADIUS authenticator within the existing framework.

** Additional context **

Example implementation in https://github.com/LawnGnome/php-radius/blob/master/examples/radius-auth.php

[AdSchellevis]

fixed in 58b1ec1

[mimugmail]

Nice :)