Remove the lightning app code (#20039)

* remove source, tests, docs, workflows

* update checkgroup

* update codeowners

* update workflows

* package setup

* config files

* update

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

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

* remove entry point

* docs

* __main__

* remove store

* leftover store removals

---------

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