www/onionshare: update 1.3.1 to 2.0

• Receiver mode allows you to receive files with OnionShare, instead of only sending files;
• Support for next generation onion services (v3);
• Public mode feature, for public uses of OnionShare,
• which when enabled turns off slugs in the URL and
• removes the limit on how many 404 requests can be made;
• If you're sharing a single file, don't zip it up;
• Full support for meek_lite (Azure) bridges;
• Several bugfixes;
• Invisible to users, but this version includes some major refactoring of the codebase, and a robust set of unit tests which makes OnionShare easier to maintain going forward;
• Allow selecting your language from a dropdown.
  
  https://raw.githubusercontent.com/micahflee/onionshare/v2.0/CHANGELOG.md

Approved by: rene (mentor)
Sponsored by: TorBSD Diversity Project, TDP
Differential Revision: https://reviews.freebsd.org/D19376