Fix consistency of READMEs with existing packages
- Swap docs/README.rst and README.rst
- move index.rst's content to README.rst
- Also fix the mimetype in setup.py
Replaces !16 (closed)
Migrated from D5360 (view on Phabricator)
Replaces !16 (closed)
Migrated from D5360 (view on Phabricator)