fix(opensource): copy storybook files to root (#4099)

* fix(storybook): serve content from root

Update push to gh pages instructions to no longer ignore storybook's output files

* fix(opensource): copy storybook files to root

Refactor gitignore for gh-pages

Author: jpan-box

.storybook/gitignore

@@ -0,0 +1,6 @@
+/*
+!.gitignore
+!LICENSE
+!package.json
+!THIRD_PARTY_LICENSES
+!storybook

scripts/cut_release.sh

@@ -144,9 +144,9 @@ push_to_gh_pages() {
     fi
     git checkout -b gh-pages || return 1
     rm -rf build
-    cp -R storybook/. ./ || return 1
-    cp examples/gitignore .gitignore || return 1 # Move this when we remove styleguidist
+    cp .storybook/gitignore .gitignore || return 1
     git rm -rf --cached . || return 1
+    cp -R storybook/. ./ || return 1
     git add -A || return 1
     git commit --no-verify -am "build(storybook): v$VERSION" || return 1
     git push release gh-pages --force --no-verify || return 1