Add repo scaffolding to meet repository standards

Add .gitignore, LICENSE (MIT), Makefile, Dockerfile, .dockerignore,
and pin prettier via yarn lockfile for integrity-checked markdown
formatting. Update REPO_POLICIES.md self-reference to point to this
repo. Format markdown files with prettier.

.dockerignore

@@ -0,0 +1,3 @@
+.git
+node_modules
+.DS_Store