net/asterisk-chan_sccp: Update to 4.3.2

• Make conference and video support optional (enabled by default)
• Add options to select different Asterisk versions
• Build for net/asterisk16 by default

While here

• Install sccp.conf with @sample
• Run it through portfmt once, fix indentation
• Reorder variables according to chapter 15 of the PHB
• Pet portlint

PR: 223972
Submitted by: maintainer