Authentication / Radius - Add MSCHAPv2 support

[AdSchellevis]

Important notices

Before you add a new report, we ask you kindly to acknowledge the following:

• [x] I have read the contributing guide lines at https://github.com/opnsense/core/blob/master/CONTRIBUTING.md
• [x] 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 (https://github.com/opnsense/ports/commit/818fa8e936b810df683afd1cf8d77cdf19d0ace3) 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 https://github.com/opnsense/core/commit/58b1ec1ea67910cafb791a445d4935f3697c13df

[mimugmail]

Nice :)