refactor: move test/ and yarn to repo root

Also lint and format entire repo, beyond just wowchemy/ dir

URL encode `(` and `)` in `[#MadeWithWowchemy](...(..)...)` in Readme.md for Prettier

test/go.mod

@@ -0,0 +1,7 @@
+module github.com/wowchemy/wowchemy-hugo-modules/test
+
+go 1.15
+
+require github.com/wowchemy/wowchemy-hugo-modules/wowchemy v0.0.0-20210202235530-9bbf6fa2a698
+
+replace github.com/wowchemy/wowchemy-hugo-modules/wowchemy => ../wowchemy