Push Handbook styles into guides_style_18f, begin updating Guides

[mtorres253]

People creating guides or other handbooks can leverage the new styles. We want to do this in a non-destructive way so that people can opt-in to the new styles rather than having them override existing styles.

[andrewmaier]

@mbland Want to pair on this?

[mbland]

Yes, but later this week. Dockerizing https://github.com/18F/knowledge-sharing-toolkit/.

[mtorres253]

@mbland @andrewmaier Have this story scheduled for grooming on Wednesday. Let's document what we want to do in the description and add an acceptance criteria before starting work on this.

[andrewmaier]

Let's incorporate the good work done by @coreycaitlin, here: 18F/guides#31