Expose multiple queues on an endpoint

It would be great if an endpoint could support both on-demand (single node) and batch (many node) jobs. However, an endpoint is configured with a single config so can only reasonably service one type of use case at a time, requiring a second endpoint to acquire nodes at a different rate. It would be nice if we could have multiple configs for a single endpoint and expose them as queues that tasks could be submitted to.

No files or tests are named. Start by tracing endpoint configuration and task submission entry points, then determine how multiple configs could be represented as queues and how on-demand and batch jobs should select them. Done means one endpoint can expose multiple configs and accept tasks for the intended queue.

Written by the indexing model from the issue text.