Better platform integration

[casimir]

When in Rome...

• [ ] Minimize on close on desktop (toggle-able)
• [ ] Visual tweaks on Apple platform (Material vs Cupertino design)
• [ ] Share extension on macOS
• [ ] xdg-open on Linux with some scheme shenanigan?
• [ ] make articles available in OS search
• [ ] Configure desktop versions for deeplinking: https://github.com/llfbandit/app_links/tree/master/doc