Add logging for Grafana metrics

[evan10s]

An easy way to analyze data about Bolt is to write logs which we can use to make graphs and track metrics in Grafana. Examples of stuff we may want to track:

• New requests
• Request status changes
• New users
• Item goes out of stock

[ehsanmasdar]

@evan10s see docs here https://github.com/HackGT/metrics