Releasing contracts as npm package

[0x3bfc]

This might be come later after moving the rust contracts into aurora-engine. We can release the solidity (artifacts) as a npm package and pypi package. So anyone can use them by importing them as module.

[sept-en]

I like the idea!

Also please note, Rust contracts from this repository won't move into aurora-engine. They were incremental steps for the eth-connector development and won't be used there.