Make README examples copy-paste runnable

[jameslamb]

Currently, there are some examples in README.md with Elasticsearch queries and corresponding uptasticsearch code. That code is effectively pseudocode right now, as it references a fictional Elasticsearch cluster.

I think this could lead to a bad experience with the docs and lead people to walk away from the project and not come back.

I would love if someone changed those examples to be runnable completely copy-paste with no editing. This project supports the ability to run Elasticsearch locally in a Docker, seeded with a sample dataset that has a few lines from some Shakespeare play.

To run ES 7.3.x locally, you can just run

./setup_local.sh 7.3

You can find example code that works with this dataset in the R package's unit tests.

We would welcome one PR for the R package (the highest priority) and then a separate PR for the Python package.