Remove Erlang term configuration examples

[lukebakken]

All RabbitMQ users should now be using rabbitmq.conf configuration files. The presence of multiple configuration options continues to confuse new users (link).

The documentation should be simplified to only show ini-style configuration, except where Erlang term configuration is absolutely necessary. At this point only LDAP requires it that I know of.

[michaelklishin]

Another place that requires it is configuration value encryption. Static Shovels is a yet another one.

I think the majority of examples already only use the .conf format but there are quite a few old blog posts, examples, configuration generation tools that have never moved away from the Erlang term format.