Legacy unused code is removed (#3832)

### Changes

* Legacy unused code is removed
* Legacy NNCFTensor is removed
* get_raw_stat_collector moved to common file
`src/nncf/common/tensor_statistics/builders.py`
* get_mean_stat_collector moved to common file
`src/nncf/common/tensor_statistics/builders.py` for ONNX/Torch
* get_mean_stat_collector moved to a file
`src/nncf/openvino/statistics/builders.py` for OpenVINO



### Reason for changes

To remove unused code and better format the repo

---------

Co-authored-by: Alexander Dokuchaev <alexander.dokuchaev@intel.com>

Author: daniil-lyakhov

.github/workflows/call_precommit.yml

@@ -119,7 +119,7 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@61cb8a9741eeb8a550a1b8544337180c0fc8476b # v7.2.0
       - name: Install test requirements
-        run: uv pip install --system -r tests/tools/requirements.txt
+        run: uv pip install --system . -r tests/tools/requirements.txt
       - name: Print installed modules
         run: pip list
       - name: Run tools precommit test scope

src/nncf/common/collector.py

@@ -9,8 +9,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-NUM_INIT_SAMPLES = 256
-
 QUANTIZATION_PRESET = "performance"
 QUANTIZE_INPUTS = True
 QUANTIZE_OUTPUTS = False