Properly initialize wiki pages

[jwMaxwell]

Is your feature request related to a problem? Please describe.
Wiki pages for this project are spread across multiple repositories. Because of this, duplicate wiki pages (such as the style-guide) will only contain a link to the original wiki page.

Describe the solution you'd like
Copy and paste the contents of all non-project specific wiki pages to the corresponding wiki pages in the .github repository. If the page doesn't exist in the .github repository, create it! Any project specific wiki pages should remain in their repo's wiki.

[brandoningli]

I'm not in favor of copy-pasting from the other wiki for the Style and Workflow guides. If updates ever have to be made, they'd have to be made in both places.

If anything, we create a profile repo (I think you can do that for orgs) and store the shared stuff in that wiki.

Edit: You can by creating a .github repo: https://docs.github.com/en/organizations/collaborating-with-groups-in-organizations/customizing-your-organizations-profile
We may even be able to migrate all our Issue/PR templates and workflows (workflows differ based on project, so that's a no-go to migrate) here and remove the .github folder from each repo.