Auto-build and publish contract ABI npm and go packages upon mainnet and public testnet migrations

Nobody has claimed this yet.

The protocol repo contains the contract ABIs after compiling the contracts. These ABIs are not only used within the protocol repo's truffle scripts but also in other client-side repos. This requires manual importing and more often than not more ABIs than necessary are imported.

We could add a script that build and publishes a new (or updated) npm package whenever we run mainnet or public testnet migrations. The public network builds would lead to a `dev` tagged package or something similar.

A first step could be to just consider the entire protocol repo as the npm package. For compiled javascript projects tree-shaking should be sufficient to avoid importing non-used ABIs in the build.

A second step could be to extract only the necessary ABIs into a very small package, this would require a little bit more work however.

We could do the same for a go package , running `abigen` and then publishing the generated files.

Alternatively we could use a CI tool to accomplish this but to avoid the built package being out of sync with the on-chain contracts it would require us to not merge changes into master before they are migrated on-chain.

No files or tests are named. Start by locating the mainnet and public testnet migration commands and the compiled ABI output, then compare the npm-package, extracted-ABI, and Go `abigen` options. Done should mean generated packages are published from migrations without becoming out of sync with on-chain contracts.

Written by the indexing model from the issue text.