Remove v1 primitive implementations

This commit removes the deprecated implementation of the v1 primitives
interface. These were deprecated in the 1.2 release and have been
superseded by the implementation of the v2 primtives interface.

qiskit/primitives/__init__.py

@@ -437,8 +437,6 @@
 
    BaseEstimator
    BaseEstimatorV1
-   Estimator
-   BackendEstimator
    EstimatorResult
 
 
@@ -450,14 +448,10 @@
 
    BaseSampler
    BaseSamplerV1
-   Sampler
-   BackendSampler
    SamplerResult
 
 """
 
-from .backend_estimator import BackendEstimator
-from .backend_sampler import BackendSampler
 from .base import (
     BaseEstimator,
     BaseEstimatorV1,
@@ -480,9 +474,7 @@
     ObservableLike,
     ObservablesArrayLike,
 )
-from .estimator import Estimator
 from .primitive_job import BasePrimitiveJob, PrimitiveJob
-from .sampler import Sampler
 from .statevector_estimator import StatevectorEstimator
 from .statevector_sampler import StatevectorSampler
 from .backend_estimator_v2 import BackendEstimatorV2