Merge pull request #18073 from vpisarev:apache2_license

changed OpenCV license from BSD to Apache 2 license

* as discussed and announced earlier, changed OpenCV license from BSD to Apache 2. Many files still contain old-style copyrights though

* changed wording a bit; preserve the original OpenCV BSD license

modules/python/package/setup.py

@@ -17,7 +17,7 @@ def main():
         name=package_name,
         version=package_version,
         url='https://github.com/opencv/opencv',
-        license='BSD',
+        license='Apache 2.0',
         description='OpenCV python bindings',
         long_description=long_description,
         long_description_content_type="text/markdown",
@@ -31,7 +31,7 @@ def main():
           'Intended Audience :: Education',
           'Intended Audience :: Information Technology',
           'Intended Audience :: Science/Research',
-          'License :: BSD License',
+          'License :: Apache 2.0 License',
           'Operating System :: MacOS',
           'Operating System :: Microsoft :: Windows',
           'Operating System :: POSIX',