Support backend.run() in IBM Cloud channel

[kt474]

We are moving the Researchers program from IQP to IBM Cloud. Since researchers are likely to be interested in functionalities provided by backend.run (e.g. dynamic circuits), we want to support backend.run() on the IBM Cloud channel as well.

Since backend.run inputs are changing, backend.run in qiskit-ibm-runtime should just accept new inputs only. People who want to use the old can continue to use qiskit-ibm-provider.

Note that backend.run() may become a third primitive, and the interface may change

[merav-aharoni]

@jyu00 - was there any discussion on what the interface should look like? Similar to backend.run() in qiskit-ibm-provider? More like circuit_runner? Wrapped as a primitive? other?

[jyu00]

Yes, the epic has more details.

tldr, it'll just be like backend.run in qiskit-ibm-provider. We may wrap it as a primitive eventually, but it'd still need to go through a deprecation period if/when that happens.