Enhance POGO detection

This change enhances the POGO detection algorithm so that it can
detect POGOs that extend or implement other types.  This change also
extracts a collection of Groovy utilities (currently centered around
detection) that are used by both the Groovy container and the Spring
Boot CLI container.

[#54518072]
Merge 54518072-pogos to master

[Completes #54518072]