See history of a git project

On the section ["ask to see the client project"](https://github.com/dwyl/process-handbook/blob/master/ProjectScopingTips.md#ask-to-see-the-existing-codebase) we can add another point on how to see the history of a git project with the `git log` command. This command can takes a few interesting options (eg `oneline`, `graph`) which can help to discover and have a global view of the project.