Further remove duplicate code and consolidate with qiskit-ibm-provider

[kt474]

In #871 and #859 we removed a lot of duplicate and unused code. There are a couple more places where we could consolidate some duplicated code with qiskit-ibm-provider. There will have to be work done in both of these repos - the code in this repo, qiskit-ibm-runtime should depend on qiskit-ibm-provider.

Related to: #969
I will try to list files that apply as I come across them:

• ibm_backend.py
• hub_group_project.py
• exception.py
• constants.py
• account management
• job
• a bunch of code in utils, like json.py, runner_result.py, etc

[kt474]

Closing this because there are plans to deprecate qiskit-ibm-provider and consolidate code into this repo