Create documentation source RST

[bsolomon1124]

Steps to render in local development:

python3 -m venv newsapi-dev
source ./newsapi-dev/bin/activate
# [cd newsapi-python/]
python -m pip install -e .
python -m pip install -r requirements-dev.txt
cd docs/
make clean && make html
open build/html/index.html

Connecting to readthedocs.io:

https://github.com/readthedocs/readthedocs.org/blob/master/README.rst#quickstart-for-github-hosted-projects

FYI @mattlisiv , it looks like you'd need to be the one to actually add this to Read The Docs. (From my account there, I'm only able to see repos under bsolomon1124/.)

Here's a sample from local development:

[mattlisiv]

Awesome. Added! https://newsapi-python.readthedocs.io