Initial draft of project metrics.

We want to develop a formula for a project score. These are the factors
that contribute to the overall score. Weighting and importance of each
of the factors will be defined in another document.
Introduce lead time, cycle time, wip and throughput.
Link to CodeClimate
Link to more sources about kanban and metrics
Merge pull request #5 from gaslight/project-metrics

Initial draft of project metrics.