[cache components]: move flag out of experimental (#85035)
This moves `experimental.cacheComponents` to a top level config. As part
of this, I disabled some tests in `build-output-prerender` that assert
on `cacheComponents` appearing in the experimental list. In a separate
PR, I'm going to show that Cache Components is enabled next to the
bundler info.
This also updates some docs pages to remove "experimental" language.
