Add integration test workflow

[LimpidCrypto]

We should have an integration test workflow that set's up a rippled node in stand-alone mode using natenichols/rippled-standalone. That way we can test if our models, like transactions get submitted properly.

References:

• https://github.com/natenichols/rippled-standalone
• https://github.com/XRPLF/xrpl-py/blob/master/.github/workflows/integration_test.yml
• https://github.com/XRPLF/xrpl.js/blob/main/.github/workflows/nodejs.yml
• https://github.com/sologenic/ripple-lib/blob/main/.github/workflows/nodejs.yml