Create doc for Contributing to nteract components docs

[willingc]

Our components documentation (https:/components.nteract.io) uses styleguidist to create the docs. To help others contribute to these docs, let's create a markdown file (createdoc-components.md) for Contributing to components documentation that includes:

• [x] What is nteract's components documentation?
• [x] What tool is used to create components documentation?
• [x] How to contribute an issue for components documentation changes or enhancements
• [x] How to install styleguidist
• [x] Where are nteract components in the nteract source code?
• [x] How to document a new component
• [x] How to build the components documentation
• [x] How to test the components documentation
• [x] How to publish the components documentation.

This document will be part of a larger nteract Documentation Contributor Guide.

[willingc]

Related to https://github.com/nteract/nteract/issues/3294

@captainsafia Let's chat about where we want the doc source files to live. I think that we have a few things:

• actual documentation of the components and styleguidist config for a components style guide (living in the nteract repo)
• documentation contributor guide which a new docs contributor lands at for all things related to contributing to docs (perhaps living here building on the work that you did on https://docs.nteract.io) similar to https://docs-dnvgccjqzi.now.sh/#/
• a short readme/note in the nteract repo linking to the detailed docs and also a minimalist "how to"