Add a style Guideline

[gpolaert]

I'm using the same as the logs-backend project.
But @tylerbenson, if you have one, just close this PR and add your style :)

[gpolaert]

I've used the Intellig reformat command on the whole project.

[tylerbenson]

How did they define this codestyle? Is it based on any existing standard codestyle?
You can find some links here on what I was thinking: https://trello.com/c/l8nx3zVx/1101-java-tracer-apply-consistent-standardized-code-style

[tylerbenson]

Going to close this until more focus can be given to the topic.