feat: added clean customization pre-commit config

[MyuddinKhatri]

Added clean customization pre-commit config. Issue - https://github.com/agritheory/test_utils/issues/5

• [x] Remove unused keys in customizations
• [x] Don't remove "default" key, even when it evaluates to False
• [x] Don't remove "value" key, even when it evaluates to False

While adding a hook to pre-commit in other repos, pass the app name to entry in the hook. entry: python3 pre-commit/clean_customized_doctypes.py {app_name} replace app_name with actual app name. eg. entry: python3 pre-commit/clean_customized_doctypes.py cloud_storage

[MyuddinKhatri]

@agritheory Should we update modified in the json as well and remind to do a bench migrate?

[agritheory]

@MyuddinKhatri Yes, I think a modified timestamp makes sense. I don't know that we need to remind to do a bench migrate, it should be fine for most workflows I can think of

[MyuddinKhatri]

@MyuddinKhatri Yes, I think a modified timestamp makes sense. I don't know that we need to remind to do a bench migrate, it should be fine for most workflows I can think of

Okay, I pushed the changes that updates modified timestamp