Fix metric computation for affine + overintegrated (#210)

* Add overintegration option for wave-op-mpi

* Add OI+lazy to examples CI testing

* Draft: Use P^0 discr on affine groups even if quad grid requested

* Refactor geoderiv connection/interpolation steps

* Fix quadrature interpolation

* Add pytato pytest array context factory

* Update metric unit tests

* Clarifying comment

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

* Add nonaffine option for wave op example

* Run lazy + nonaffine + overintegration in examples CI testing

* Add quadrature case for metric unit tests

* Add optional import for debugging outside of pytest

* Add docstrings for _use_geoderiv_connection

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