Expand API Tests and SDK for Commands Endpoint

[jaredbroad]

Expected Behavior

API SDK included coverage of the command endpoint.

Actual Behavior

No command endpoint available

Potential Solution

Document and include the command endpoint

Checklist

• [x] I have completely filled out this template
• [x] I have confirmed that this issue exists on the current master branch
• [x] I have confirmed that this is not a duplicate issue by searching [issues](https://github.com/QuantConnect/Lean/issues

[Martin-Molinero]

Live liquidate & stop endpoints are implemented & documented atm TODO Add security, place order, cancel order, lean CLI cloud commands also missing these