Integration tests for dispatch and poll

[vprusso]

As the backends tend to change their APIs, etc., including integration tests that can run on at least simulator backends (i.e., poll and dispatch the supported benchmarks) would be prudent.

At a minimum, these integration tests would include the ability to launch a simulator instance for each supported backend (e.g., IBM, IonQ, etc.) and successfully poll and dispatch results.

Access to some simulator backends also requires account access (for instance, IonQ requires this), in which case, we will need to create a metriq-gym-specific account and store the credentials in a project-level variable for accessing and running these integration tests.