This commit moves zoneless from experimental to developer preview.
* Update tag on provider API
* Remove "experimental" from provider name
* Move documentation from "experimental features" to "Best practives ->
Performance" (at least temporarily until there is a better place)
BREAKING CHANGE: `provideExperimentalZonelessChangeDetection` is
renamed to `provideZonelessChangeDetection` as it is now "Developer
Preview" rather than "Experimental".
PR Close#60748
To increase the ease of development we are moving @angular/docs into the adev directory within this repo. While
we are doing this to improve our development experience in the short term, efforts are also in place
to maintain a division between this @angular/docs (shared) code and adev itself, so that it can be extracted
back out in the future when components is ready to leverage it as well.
PR Close#57132
