add order chains, add is_market_open_on util

[Graeme22]

Description

Adds a way to fetch order chains manually (previously only available in account streamer)
Adds a utility function, is_market_open_on to check market calendar for a given date.

Pre-merge checklist

• Code formatted correctly (check with make lint)
• Code implemented for both sync and async
• Passing tests locally (check with make test, make sure you have TT_USERNAME, TT_PASSWORD, and TT_ACCOUNT environment variables set)
• New tests added (if applicable)

Please note that, in order to pass the tests, you'll need to set up your Tastytrade credentials as repository secrets on your local fork. Read more at CONTRIBUTING.md.