1.2 All remaining Rust connection node issues from previous quarter have been closed.

[bbangert]

Issues:

• Extract debug info for traceback autopush#1002
• Add statsd metric reporting to Rust version autopush#1054
• Ensure Rust log output fully meets production format autopush#1055
• Add tests for the Rust connection handling autopush#1060
• Implement PUT /notif/ in Rust autopush#1062
• Implement NACK messages in Rust autopush#1063
• Use Sentry for error reporting in Rust code autopush#1066
• fix ctrl-c not working under autopush_rs autopush#1090
• Consider user agent differences in autopush_rs autopush#1121
• Drain notification queue on client drop autopush#1133