CI: clean install & share pkg build (#15986)
* abstract pkg build
* share ci
* syntax
* Checkgroup
* folders
* whl 1st
* doctest
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Carlos Mocholí <carlossmocholi@gmail.com>
