Migrate from imp to importlib

[david-geiger]

• the 'imp' module is deprecated from years and now Python 3.12 finally drops completely support of 'imp' module.
• fix for module "imp" was deprecated in python 3.12 #107

[BenjamenMeyer]

Your original PR is good to do against our master (0.10.x) branch. Please rebase this against our 0.9.x branch. Ultimately we need to do 2 PRs.

$ git checkout -b bugfix_imp-to-importlib_0.9.x
$ git rebase 0.9.x

# If it doesn't cleanly rebase the do this to resolve conflicts 
$ git mergetool
$ git rebase --continue

# when done
$ git push origin bugfix_imp-to-importlib_0.9.x
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