news/inn{-current}: Modernize the port

Update to modern ports practices while retaining same functionality.

• Option helpers
• GNU_CONFIGURE with overrides for existing filesystem layout
• USES gssapi for krb5, clean up ac_cv_ hacks
• Fix setuid for SETGID_INEWS and UUCP_RNEWS
• Add newer config files as @sample: inn-radius.conf, inn-secrets.conf
• Install all filter scripts as @sample
• Remove ex script and install empty history as @sample
• Use find to run bin/.so strip list instead of manual list
• Clean up inn-current slave port
• portclippy