docs: move fabric on its own (#16742)

* docs: move fabric to Lai

* update imports

* links

* drop link to Trainer

* own docs

* ci

* trigger

* prune cross-links

* cleaning

* cleaning

* template

* imports

* template

* path

* links

* tensorboardX

* plugins

* label

* drop fixme

* drop copy nb + examples

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Apply suggestions from code review

* try again

* rev

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>