Need handling and tests for config key/values inside other than '=config' blocks

[tbrowder]

For example, given the following, extract the configuration data

=begin pod
=for para :align<center>
Howdy!
=end pod

[tbrowder]

I am in the process of ensuring the "test" listener handles most, if not all, Pod6 block types, including the .config method and other methods provided by some types. Thus it should be able to be used by other modules attempting to use Pod6 for pratical projects.

I am also adding tests to see the effects of impending RakuAST usage affects Pod6 handling.