chore(getting-started): load our GETTING_STARTED.md in the docs (closes #504)

[emoralesb05]

we need to show our GETTING_STARTED information easier by loading it in the docs site.

#504

What's included?

• load our docs/ dir as part of the build.
• Loading GETTING_STARTED.md with our pretty-markdown component

Test Steps

• ng serve
• Go to http://localhost:4200/#/docs
• See the https://github.com/Teradata/covalent/blob/develop/docs/GETTING_STARTED.md being loaded

General Tests for Every PR

• ng serve --aot still works.
• npm run lint passes.
• npm test passes and code coverage is not lower.
• npm run build still works.

Screenshots or link to CodePen/Plunker/JSfiddle

[richavyas]

LGTM