Add coordinator wrapper

[xianny]

Description

Adds a wrapper for handling Coordinator transactions

Testing instructions

cd packages/contract-wrappers && yarn build && yarn test

Unit tests cover fills, soft cancels, hard cancels, and handling server errors.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• Prefix PR title with [WIP] if necessary.
• Add tests to cover changes as needed.
• Update documentation as needed.
• Add new entries to the relevant CHANGELOG.jsons.

[dekz]

It looks like this is bringing in some old dependencies of contract-wrappers, might result in some strange behaviour.

[xianny]

I'd still like to write more tests for error cases to check the format of the errors, but apart from that I've implemented all the changes brought up.

I changed everything to return Promise<txhash | CoordinatorError> at first, then changed it back to throw errors. But had to stringify CoordinatorError objects. Feeling ambivalent about this. If we return instead of throwing, it breaks the resolve/reject interface for Promises. Is there a way to throw an error with an object instead of just a string?

[fabioberger]

LGTM once CI tests pass

[xianny]

static-tests-python is failing everywhere else too. I'm going to call it unrelated and merge this. 🎉