* chore(v2): Add E2E test for yarn v2
* Remove root node_modules to prevent them from accessible in e2e test
The purpose of e2e test is to ensure that the docusaurus inited website can stand on its own. The root node_modules remain accessible according to how node resolution works and it might interfere with the test. Remove them for safety.
* Add @mdx-js/react to docusaurus init templates