Add support for specifying task hub and connection name for `client.startNew()`

As in title, moving this TODO line into an issue instead: https://github.com/Azure/azure-functions-durable-js/blob/4b4eae8a5dc9b1571be6cdfda229b7ae2d0fba4a/src/durableorchestrationclient.ts#L666

This may have dependencies the extension as well

Start at src/durableorchestrationclient.ts around line 666, where the referenced TODO is located, and trace how client.startNew() currently handles its options. Check whether the feature depends on the Durable Functions extension. Done means startNew() can specify both a task hub and a connection name, with the extension dependency resolved.

Written by the indexing model from the issue text.