Replace Logrus with Zap and adjust ENV=local output format

[ryanrolds]

Logrus has recently been put into maintenance mode. Replace Logrus with Zap. When the ENV env var is local, output more human-readable (non-JSON) logs to STDOUT. When non-local, output JSON.

If possible, colorize the more human-readable output (ConsoleEncoder). Also try to include function, filename, and line number in the output (currently being outputted with Logrus).