Use com.linkedin.restli.server.NoMetadata to mark a finder's CollectionResult as no metadata.
Allow non-template return type for finders.

RB=165359
R=adubman,jbetz,slim,si-dev,cmiyamot
A=adubman,slim,cmiyamot
IDL compatibility checks for new methods, finders, actions and subresources.
Fix test failure in TestResourceSchemaCollection.
Fix test failure in TestRestLiResourceModels.