Send logs to file

[jamesbornholt]

Currently we have no way to log to a file—logs are always printed to stderr. This is particularly annoying for metrics, which are spammed to the console every few seconds. We should have a way to redirect logs to a file. This will be more important once we do #30.

[dannycjones]

We ask for logs as part of our bug report template (#56). We should update that template so its clear how to configure and enable log, likely just linking through to documentation.

[eslrahc-swa]

High level goal:

• segregate different log levels and makes it convenient to engineers for a better reasoning.

[jamesbornholt]

#91