python: bindings loader package

Configures and loads OpenCV bindings extension including 3rdparty dependencies

Based on running Python specify:
- configure PYTHON_PATH (via "sys.path")
- configure LD_LIBRARY_PATH / PATH

modules/python/package/cv2/load_config_py2.py

@@ -0,0 +1,6 @@
+# flake8: noqa
+import sys
+
+if sys.version_info[:2] < (3, 0):
+    def exec_file_wrapper(fpath, g_vars, l_vars):
+        execfile(fpath, g_vars, l_vars)