validate: T3418: interface-name should also allow all local present interfaces

The regex only validated interfaces according to the VyOS naming scheme, but
third party interfacs that are legit (e.g. exists within the kernel) failed
to validate.

The validator now also supports any kind of local interfaces attached to
the OS kernel.

(cherry picked from commit 911fe645928750f3ce38061a94c9b6db50db0749)