Support for Cloud Foundry .profile files in build repackagers

[youngm]

With Spring boot 1.4 and the refactor of the maven plugin to support LayoutFactory all my Spring Boot apps that deploy to CloudFoundry and use a .profile file have broken. https://docs.cloudfoundry.org/devguide/deploy-apps/deploy-app.html#profile

It would be great if spring boot either:
a. Provided a layout factory like the old one that put src/main/resources in the root of the executable jar.
b. Added repackager config that allowed for a set of files to be put into the root of the produced executable jar.

Thoughts?

[wilkinsona]

Duplicates #6626