remove source maps from distributed package

[kubikowski]

Ultimately, when it comes to the decision over which files to publish in the distributed package, there are two options to consider:

1. Publish both sources & source maps.
2. Publish neither sources nor source maps.

This is because, fundamentally, in order for end users to use source maps for debugging purposes, they would need the associated sources available in the package.

Given that we currently do not currently publish sources: option 1 would mean adding sources to the package, whereas option 2 would be to remove the source maps. And after some npm publish --dry-run testing, the differential end result is that adding sources would increase the package size by ~100% over removing source maps.

Further reading on the discussion: googleapis/google-cloud-node#2867