Better Test Wiring Support for ConfigurationProperties

I have a ServiceUnitTest that is failing because on my Grails Service, I'm injecting an object annotated with `@ConfigurationProperties(PREFIX)` and the bean isn't being defined by the ServiceUnitTest.

Plugins like grails-mail have moved to configurationProperties so we should consider adding better support in our test framework to autowire these in unit tests.

Start with the failing ServiceUnitTest described in the issue and trace how its injected @ConfigurationProperties(PREFIX) bean is registered. Reproduce the grails-mail configurationProperties case; done means the configuration-properties object is available for autowiring in ServiceUnitTest without breaking existing tests.

Written by the indexing model from the issue text.