Auto-mocking extension code was removed

[Hamled]

In commit 2c29dc2 the zip files used for auto-mocking in unit and integration tests were removed.

While those zip files did contain copies of the mocking libraries (Moq and NSubstitute), and those libraries can be obtained from other sources such as nuget (the docs were later updated to reflect that). However, the zip files also contained some Zenject-specific code to provide the extension methods that are discussed in the code samples in the auto-mocking documentation.

Currently it seems that the auto-mocking documentation cannot be followed as the extension methods are unavailable even when the third-party mocking libraries are installed. The documentation for auto-mocking should perhaps be removed, or possibly the necessary code should be added back into the repo from those zip files. I'm not sure if the latter option is possible as that code likely would not build unless the library it depends upon is present.