Rewrite example configuration

[SpacemanPaul]

ows_cfg_example.py is poorly maintained, and does not reflect current best practice. The current file has a lot of now-unnecessary complexity from when it was the only documentation of configuration options.

Ideally:

1. Made more minimalist and basic. Doesn't need to include every single config option. Users with advanced requirements should be referred to the documentation.
2. A multi-file example directory, as per the layout of the current DEAus/DEAfrica config (but smaller and more minimal than either).

[SpacemanPaul]

Beefed up the disclaimer at the top of the file and added note to README to take it with a grain of salt.