Remove pkg_resources runtime usage

[Mirochill]

Fixes #471.

Summary

• replace Mikado runtime pkg_resources resource access with a small importlib.resources helper
• update Daijin Snakefiles and sample Snakefile resource paths to use the same helper
• remove the temporary setuptools<80.9 pins from runtime/build environment metadata

Validation

• git diff --check HEAD~1..HEAD
• rg -n pkg_resources|resource_filename|resource_stream|setuptools<80\.9|setuptools<81 Mikado\subprograms Mikado\configuration Mikado\daijin sample_data setup.py setup.cfg pyproject.toml requirements.txt environment.yml returned no matches
• Not run locally