Check zip-safe in addition to __file__

The (not-)zip-safe file in the package metadata is often a good indicator of whether `__file__` is being used. By default setuptools creates that file doing similar inspection that PyOxidizer is doing.

However packages which use `__file__` but also fall back gracefully can override it with `setup(zip_safe=True)`. This scenario could be used to turn off the notice about `__file__`, and instead provide a list of packages which have overridded `zip-safe`.

The presence of `not-zip-safe` means there is already existing metadata declaring the package can not be safely used except on-disk. IMO these should be a build time error, bypassed only with an `--ignore-zip-safe` or similar.

Start by tracing PyOxidizer's existing __file__ inspection and the handling of package metadata generated by setuptools. Determine how not-zip-safe and an overridden zip_safe=True should affect notices, and define the build-time error and --ignore-zip-safe behavior described in the issue.

Written by the indexing model from the issue text.