Download Go binaries instead of packaging them up

[bittner]

Currently, we package Go binaries for all supported target OSes with the Python package to allow for easy installation of all dependencies.

While this is convenient it has some technical challenges (see #3) and increases the Python package size significantly (currently 53.7 MB).

Expected result

Evaluate whether it makes sense (and is technically possible, in a clean way) to download the necessary Go binaries upon installation of the Python package.

[bittner]

Package size is definitely smaller now (currently 8.5 kB). 🎊

Go binaries are downloaded lazily and installed locally before they're need the first time.