Here we put Ado::Plugin::* specific configuratuon files.  

The files must be named after the plugins for which they contain configuration.
A plugin Ado::Plugin::Hello will search its configuration
$app->home->rel_dir('etc/plugins/hello.conf').  The file must return a HASHREF:
(the app keyword containing the current application instance is available for
use) #etc/plugins/hello.conf { somekey =>'somevalue' #...  };

The default settings can be changed in the common etc/ado.conf at
$app->config('plugins')->{hello}; See etc/ado.conf for examples.

