src layout (#3560)

### Changes

Updated structure of project to src layout 

### Reason for changes


https://packaging.python.org/en/latest/discussions/src-layout-vs-flat-layout/

### Tests

Author: AlexanderDokuchaev

MANIFEST.in

@@ -1,6 +1,6 @@
-graft nncf/torch/extensions
-graft nncf/common/hardware/configs
+graft src/nncf/torch/extensions
+graft src/nncf/common/hardware/configs
 include LICENSE
 include licensing/third-party-programs.txt
 include docs/PyPiPublishing.md
-include custom_version.py
+include src/custom_version.py

README.md

@@ -35,7 +35,7 @@
 # using :type: syntax.
 autodoc_typehints = "description"
 
-autoapi_dirs = ["../../../nncf"]
+autoapi_dirs = ["../../../src/nncf"]
 autoapi_options = ["members", "show-inheritance", "show-module-summary", "special-members", "imported-members"]
 
 autoapi_template_dir = "_autoapi_templates"
@@ -190,7 +190,7 @@ def skip_non_api(app, what, name, obj, skip, options):
 def linkcode_resolve(domain, info):
     # sphinx.ext.linkcode interface; will link to Github here.
     target_ref = "develop"
-    base_url = f"https://github.com/openvinotoolkit/nncf/blob/{target_ref}/"
+    base_url = f"https://github.com/openvinotoolkit/nncf/blob/{target_ref}/src/"
     if not info["module"]:
         return None
     fullname = info["module"] + "." + info["fullname"]

docs/ConfigFile.md

@@ -65,8 +65,7 @@ Homepage = "https://github.com/openvinotoolkit/nncf"
 version = { attr = "custom_version.version" }
 
 [tool.setuptools.packages.find]
-where = ["."]
-exclude = ["tests", "tests.*", "examples", "examples.*", "tools", "tools.*"]
+where = ["src"]
 namespaces = false
 
 [tool.md_dead_link_check]
@@ -80,15 +79,15 @@ strict = true
 # https://github.com/hauntsaninja/no_implicit_optional
 implicit_optional = true
 files = [
-    "nncf/api",
-    "nncf/data",
-    "nncf/common",
-    "nncf/config",
-    "nncf/torch/function_hook",
-    "nncf/quantization/*py",
-    "nncf/telemetry/",
-    "nncf/tensor/",
-    "nncf/*py",
+    "src/nncf/api",
+    "src/nncf/data",
+    "src/nncf/common",
+    "src/nncf/config",
+    "src/nncf/torch/function_hook",
+    "src/nncf/quantization/*py",
+    "src/nncf/telemetry/",
+    "src/nncf/tensor/",
+    "src/nncf/*py",
 ]
 disable_error_code = ["import-untyped"]
 
@@ -100,8 +99,8 @@ disable_error_code = ["empty-body", "no-any-return"]
 [tool.ruff]
 line-length = 120
 exclude = [
-    "nncf/tensorflow/__init__.py",
-    "nncf/torch/function_hook/handle_inner_functions.py"
+    "src/nncf/tensorflow/__init__.py",
+    "src/nncf/torch/function_hook/handle_inner_functions.py"
 ]
 
 [tool.ruff.lint]
@@ -162,12 +161,12 @@ extend-select = [
 ]
 
 [tool.ruff.lint.per-file-ignores]
-"nncf/experimental/torch/nas/bootstrapNAS/__init__.py" = ["F401"]
-"nncf/torch/__init__.py" = ["F401", "E402"]
+"src/nncf/experimental/torch/nas/bootstrapNAS/__init__.py" = ["F401"]
+"src/nncf/torch/__init__.py" = ["F401", "E402"]
 "tests/**/*.py" = ["F403"]
 "tests/**/__init__.py" = ["F401"]
 "examples/**/*.py" = ["F403"]
-"!nncf/**.py" = ["INP", "D"]
+"!src/nncf/**.py" = ["INP", "D"]
 
 [tool.ruff.lint.flake8-copyright]
 notice-rgx = """\

docs/PyPiPublishing.md

@@ -23,7 +23,7 @@
 1. **NNCF_RELEASE_BUILD**:
     - Set this environment variable to generate a release package using `python -m build` without including
       the commit hash in the version.
-    - If this variable is not set, the file `nncf/version.py` will be overridden with a custom version
+    - If this variable is not set, the file `src/nncf/version.py` will be overridden with a custom version
       that includes the commit hash. Example usage:
 
         NNCF_RELEASE_BUILD=1 python -m build
@@ -35,12 +35,12 @@
 
 Post-Build Recommendation:
 ---------------------------
-After generating the package, it is recommended to revert any changes to `nncf/version.py` to avoid potential conflicts.
+After generating the package, revert changes to src/nncf/version.py to prevent possible conflicts.
 This can be done using the following command:
 
-    git checkout nncf/version.py
+    git checkout src/nncf/version.py
 
-This ensures that `nncf/version.py` remains in its original state after the dynamic versioning process.
+This ensures that `src/nncf/version.py` remains in its original state after the dynamic versioning process.
 """
 
 from __future__ import annotations
@@ -51,7 +51,7 @@
 import subprocess
 from pathlib import Path
 
-NNCF_VERSION_FILE = "nncf/version.py"
+NNCF_VERSION_FILE = "src/nncf/version.py"
 
 
 def get_custom_version() -> str: