Updating description and adding long description

Author: aliabbasrizvi

setup.py

@@ -20,7 +20,11 @@
 setup(
     name='optimizely-sdk',
     version=__version__,
-    description="SDK for Optimizely's Full Stack Python project.",
+    description='Python SDK for Optimizely X Full Stack.',
+    long_description='Optimizely X Full Stack is A/B testing and feature management for product development teams. '
+                     'Experiment in any application. Make every feature on your roadmap an opportunity to learn. '
+                     'Learn more at https://www.optimizely.com/products/full-stack/ or see our documentation at '
+                     'https://developers.optimizely.com/x/solutions/sdks/reference/index.html?language=python',
     author='Optimizely',
     author_email='[email protected]',
     url='https://github.com/optimizely/python-sdk',