Aligning our illustration styles

Related to [meta] Evolving the GitLab Visual Personality

We have recently created a lot of awesome illustrations for the Getting Started pages on GitLab (#15632 (closed)). We should consider how these illustration styles relate to the illustrations currently used on our Marketing website, and see if there are opportunities for alignment.

Examples from about.gitlab.com Screen_Shot_2016-11-08_at_2.47.10_PM Screen_Shot_2016-11-08_at_2.50.53_PM Screen_Shot_2016-11-08_at_2.47.44_PM