Inline a react and react-dom for app dir, when `appDir` flag is enabled
opt into the built-in version for all.
For server layer react, use the react share subset for server
components.
For all server side of react-dom usage, use the server-rendering-stub.
Co-authored-by: Shu Ding <g@shud.in>
Co-authored-by: JJ Kasper <jj@jjsweb.site>
