Add backend related functions in RuntimeClient (#55)

* Add backend related functions in RuntimeClient

* Removing timeout since no longer needed

The new API just returns the string of backends and not all the configuration at once, so we don't need to provide user with the option to specify a custom timeout since the get backends call won't take too long for IBM Cloud

qiskit_ibm_runtime/api/clients/runtime.py

@@ -13,7 +13,7 @@
 """Client for accessing IBM Quantum runtime service."""
 
 import logging
-from typing import Any, Dict, Optional
+from typing import Any, Dict, List, Optional
 
 from qiskit_ibm_runtime.credentials import Credentials
 from qiskit_ibm_runtime.api.session import RetrySession
@@ -278,3 +278,57 @@ def job_logs(self, job_id: str) -> str:
     def logout(self) -> None:
         """Clear authorization cache."""
         self.api.logout()
+
+    # IBM Cloud only functions
+
+    def list_backends(self) -> List[Dict[str, Any]]:
+        """Return IBM Cloud backends available for this service instance.
+
+        Returns:
+            IBM Cloud backends available for this service instance.
+        """
+        return self.api.backends()
+
+    def backend_configuration(self, backend_name: str) -> Dict[str, Any]:
+        """Return the configuration of the IBM Cloud backend.
+
+        Args:
+            backend_name: The name of the IBM Cloud backend.
+
+        Returns:
+            Backend configuration.
+        """
+        return self.api.backend(backend_name).configuration()
+
+    def backend_status(self, backend_name: str) -> Dict[str, Any]:
+        """Return the status of the IBM Cloud backend.
+
+        Args:
+            backend_name: The name of the IBM Cloud backend.
+
+        Returns:
+            Backend status.
+        """
+        return self.api.backend(backend_name).status()
+
+    def backend_properties(self, backend_name: str) -> Dict[str, Any]:
+        """Return the properties of the IBM Cloud backend.
+
+        Args:
+            backend_name: The name of the IBM Cloud backend.
+
+        Returns:
+            Backend properties.
+        """
+        return self.api.backend(backend_name).properties()
+
+    def backend_pulse_defaults(self, backend_name: str) -> Dict:
+        """Return the pulse defaults of the IBM Cloud backend.
+
+        Args:
+            backend_name: The name of the IBM Cloud backend.
+
+        Returns:
+            Backend pulse defaults.
+        """
+        return self.api.backend(backend_name).pulse_defaults()