* Replace custom type names with _doc in REST examples.
* Avoid using two mapping types in the percolator docs.
* Rename doc -> _doc in the main repository README.
* Also replace some custom type names in the HLRC docs.
This commit adds two pieces. The first is a small set of documentation providing
instructions on how to get setup to run context examples. This will require a download
similar to how Kibana works for some of the examples. The second is an ingest processor
example using the downloaded data. More examples will follow as ideally one per PR.
This also adds a set of tests to individually test each script as a unit test.