Primitives (non runtime) changes for 1.0 (#812)

Closes #1072 

Some helpful background: from Jessie: The goal of this document is for
people to test their quantum program (that calls primitives) locally,
before sending them to Qiskit Runtime to run on a real QPU.

Most of this page uses the statevector simulator, and there is an
equivalent for V2, better named as
[StatevectorEstimator](https://github.com/Qiskit/qiskit/blob/main/qiskit/primitives/statevector_estimator.py#L31)
and
[StatevectorSampler](https://github.com/Qiskit/qiskit/blob/main/qiskit/primitives/statevector_sampler.py#L52).

---------

Co-authored-by: Ian Hincks <ian.hincks@gmail.com>
Co-authored-by: abbycross <across@us.ibm.com>
Co-authored-by: Elena Peña Tapia <epenatap@gmail.com>
Co-authored-by: Elena Peña Tapia <57907331+ElePT@users.noreply.github.com>

docs/run/primitives-get-started.mdx

@@ -20,7 +20,7 @@ service = QiskitRuntimeService(channel="ibm_cloud", channel_strategy="q-ctrl")
 </Admonition>
 
 <Admonition type="note">
-    These examples all use the primitives from Qiskit Runtime, but you could use the base primitives instead. 
+    While this documentation uses the primitives from Qiskit Runtime, which allow you to use IBM&reg; backends, the primitives can be run on any provider by using the [backend primitives](#backend) instead.  Additionally, you can use the *reference* primitives to run on a local statevector simulator.  See [Exact simulation with Qiskit primitives](../verify/simulate-with-qiskit-primitives) for details.
 </Admonition>
 
 <span id="start-estimator"></span>
@@ -236,6 +236,35 @@ print(f"  > Metadata: {result.metadata[0]}")
   </TabItem>
 </Tabs>
 
+<span id="backend"></span>
+## Get started with the backend primitives
+
+The `Sampler` primitive can be run with any provider by using [`qiskit.primitives.BackendSampler`](../api/qiskit/qiskit.primitives.BackendSampler). Likewise, the `Estimator` primitive can be run with any provider using [`qiskit.primitives.BackendEstimator`](../api/qiskit/qiskit.primitives.BackendEstimator). Equivalent implementations in V2 are coming soon.   
+
+Some providers implement primitives natively (see [the Qiskit Ecosystem page](https://qiskit.github.io/ecosystem#providers) for more details).
+
+### Example: BackendEstimator
+
+```python
+from qiskit.primitives import BackendEstimator
+from <some_qiskit_provider> import QiskitProvider
+
+provider = QiskitProvider()
+backend = provider.get_backend('backend_name')
+estimator = BackendEstimator(backend)
+```
+
+### Example: BackendSampler
+
+```python
+from qiskit.primitives import BackendSampler
+from <some_qiskit_provider> import QiskitProvider
+
+provider = QiskitProvider()
+backend = provider.get_backend('backend_name')
+sampler = BackendSampler(backend)
+```
+
 ## Next steps
 
 <Admonition type="tip" title="Recommendations">