Refactor to run mypy in docker

[eirikurj]

Purpose

mypy expects modules imported to exist during CI check, such as mpi4py, which in turn depends on MPI. Instead of having to install everything or write and maintain stub files, we instead run mypy in our Docker containers. This provides the added benefit that its directly checked against our dev environment.

Expected time until merged

The dev docker containers need to be updated before (see https://github.com/scritical/docker/pull/15)

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Checklist

• I have run ruff check and ruff format to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[DavidAnderegg]

looks good.