Add login

## Problem

Visilibity on past LHM runs is very low, and makes it for terrible head aches

## Solution

Add logging to LHM:

We have found that having logs would improve our workflow, this commit simply adds a Lhm wide logger, which is just a simple ruby Logger instance, it must be configured once before the first call to Lhm.logger, via the ```Lhm.logger_params```
accessor, probably from a Rails initializer.


@arthurnn @sroysen