GEODE 608: Initial cut at adding RAT to build
GEODE 608: Initial cut at adding RAT to build

Add the RAT plugin to check for license headers in source files.  This
is a first pass that excludess generated files, typical IDE files, etc.
Create the report using `gradle rat`.  As GEODE-18 continues we can
update the excludes list appropriately.  Eventually this task should
pass.

jdeppe-pivotal/geode,pdxrunner/geode,deepakddixit/incubator-geode,pivotal-amurmann/geode,masaki-yamakawa/geode,PurelyApplied/geode,masaki-yamakawa/geode,davebarnes97/geode,prasi-in/geode,smgoller/geode,pivotal-amurmann/geode,pdxrunner/geode,masaki-yamakawa/geode,pdxrunner/geode,jdeppe-pivotal/geode,pdxrunner/geode,shankarh/geode,masaki-yamakawa/geode,smanvi-pivotal/geode,davinash/geode,smgoller/geode,charliemblack/geode,masaki-yamakawa/geode,davinash/geode,masaki-yamakawa/geode,pivotal-amurmann/geode,masaki-yamakawa/geode,deepakddixit/incubator-geode,charliemblack/geode,davinash/geode,pivotal-amurmann/geode,deepakddixit/incubator-geode,PurelyApplied/geode,jdeppe-pivotal/geode,deepakddixit/incubator-geode,shankarh/geode,prasi-in/geode,prasi-in/geode,pdxrunner/geode,davinash/geode,PurelyApplied/geode,smanvi-pivotal/geode,davebarnes97/geode,davebarnes97/geode,pdxrunner/geode,PurelyApplied/geode,charliemblack/geode,deepakddixit/incubator-geode,jdeppe-pivotal/geode,pdxrunner/geode,smanvi-pivotal/geode,shankarh/geode,PurelyApplied/geode,davebarnes97/geode,shankarh/geode,deepakddixit/incubator-geode,charliemblack/geode,pivotal-amurmann/geode,jdeppe-pivotal/geode,smgoller/geode,PurelyApplied/geode,jdeppe-pivotal/geode,davinash/geode,shankarh/geode,davinash/geode,charliemblack/geode,PurelyApplied/geode,smgoller/geode,prasi-in/geode,davebarnes97/geode,davinash/geode,smgoller/geode,davebarnes97/geode,jdeppe-pivotal/geode,deepakddixit/incubator-geode,smanvi-pivotal/geode,prasi-in/geode,smgoller/geode,smgoller/geode,smanvi-pivotal/geode,davebarnes97/geode