www/waterfox: remove expired port
- Old style system (pre-Stylo) is no longer maintained for vulnerabilities
- FreeBSD lacks process sandboxing to protect against any undisclosed vulnerabilities
- Backporting from current Firefox releases to 56.* codebase is non-trivial
- During 57-60 timeframe many compatibility bridges have been burnt, so the next release based on ESR60 is likely to require porting extensions to it
- www/firefox-esr can be built with MOZ_EXPORT+=MOZ_ALLOW_LEGACY_EXTENSIONS=1 in Makefile.local which would make it act similar to Nightly or Waterfox 60.*
- www/firefox privacy can be enhanced via about:config, for anything more porting Tor Browser would be a better option