Publish to crates.io

[ascjones]

Now that there are up to date crates released to crates.io, we should use those dependencies, and also publish substrate-contracts-node there.

We would need https://github.com/Brushfam/pallet-assets-chain-extension to be published to crates.io, or could copy it into this repository.

[deuszx]

Or we can remove the extension entirely from the subtrate-contracts-node. It seems like a random thing. Do we even know for sure that it's working correctly? There's no CI in the repo or tests.

[ascjones]

#204

[ascjones]

https://crates.io/crates/contracts-node