Make use of github actions for CI and release [$1080]
`monero-ts` can benefit from GH Actions for CI, running tests on new commits in branches and PRs, detect changes to C++ code and rebuild emscription. Also package the release to be deployed on NPM upon new `release` action.

This approach will make use of docker environment for reproducible builds and for running the `monerod` and `monero-wallet-cli` in tests.

See how we did it in [mainnet-cash/mainnet-js](http://github.com/mainnet-cash/mainnet-js)