API documentation has broken links

[beckykd]

• ibm_backend.py links to these locations that no longer exist:
  backend_configuration_schema.json
  backend_properties_schema.json
  default_pulse_configuration_schema.json

• qiskit-runtime-service has broken links to:
  https://auth.quantum-computing.ibm.com/api
  auth.quantum.ibm.com/api
  quantum-computing.cloud.ibm.com