Explains why pytato was being added as a requirement for downstream
packages.

- add pytato to requirements.txt of downstream projects to make them
  compatible with PytatoArrayContext

* add run-mypy.sh

* use for github CI

* add to gitlab

* mypy -> python -m mypy

Co-authored-by: Andreas Klöckner <inform@tiker.net>

* enable mypy in setup.cfg

* add some more type annotations

* add py.typed

* add mypy to ci

* fix some type annotations

* CI: drop insecure curl, add downstreams, simplify

* Use conda for pylint, don't install mpi4py

* Drop pytential from downstream CI

* Move array context functionality over from meshmode

Co-authored-by: Alex Fikl <alexfikl@gmail.com>

* Drop sphinx version requirement

* Fix replica DOFArray in tests for pylint

Co-authored-by: Alex Fikl <alexfikl@gmail.com>