[change] Migrate to freeradius 3.2 by default

[nemesifier]

Since Freeradius 3.2 is available on all modern distros, once we have released the new version, we should drop support for old operating systems and default to Freeradius 3.2.

[himanshu-sharmav]

@nemesifier I would like to work on this, can we discuss on the process, on what exactly we have to do?

[nemesifier]

@himanshu-sharmav leave this to us as it's a maintenance tasks that requires a bit of knowledge of the situation in this ansible role.