Add module federation plugin

[MrLeebo]

• Adds module-federation plugin, allowing cms to import components such as Breadcrumb and SiteTour from n360

   import Breadcrumb from "host/breadcrumb";

• Adds tsconfig and enable ts checking for .js files
• Run npm run start:mf to serve federated content at http://localhost:8080/remoteEntry.js
• Currently is only serving the "hello-world" blog post's pageData because I haven't figured out how to federate gatsby templates yet

[MrLeebo]

I'm somewhat torn between whether to define pages using the file-based framework (e.g. src/pages/faq.tsx) vs creating each page definition with createPage() in gatsby-node.js. createPage() offers a little better control over the shape of the pageData and there are not as many unused fields in the object, but src/pages/ requires less boilerplate when creating a new page.

[MrLeebo]

@nsmmrs please review this PR and create a new branch for your FAQ import script changes, and we'll get this merged in

[nsmmrs]

@MrLeebo Will do.