Merge rabbitmq_config_spec.rb into main rabbitmq_spec.rb.

We're merging these together as we want to keep testing restricted
to entry point classes, hiding these other classes altogether, as
they shouldn't be used as primary sources at all.
Refactor classes to only have a single entry point class, to validate
params, and add rabbitmq::management.

These changes combined make sure that class parameters can only be set
on the main rabbitmq class and not overridden on subclasses.  As a
consequence of this we need to properly validate the parameters passed
in.

Rabbitmq::management is the post ::service class for providers that
require the service to be up.
Various changes to fix typing of variables.

Turns out that adding all this validation was a good idea as it caught
numerous cases where I set a default to false (boolean) but then treated
that variable like another type, which is just bad manners.
Test against the main class.

Handle all the changes to params and to ensure we're always describing
the main rabbitmq class rather than testing individual classes as if
they can stand alone when they cannot.