CopyrightReviewApi to update gerrit review threads.

Copyright plugin part 1 of 3: CopyrightReviewApi manages and updates
gerrit code review threads with findings found in new pushed revisions.

CopyrightConfig is a stripped down shell of only what is needed for
CopyrightReviewApi and its tests to build and run. Part 2 will expand
CoprightConfig with listeners and code to parse, validate and load
plugin/scanner configurations.

Part 3 will introduce CopyrightValidator to scan the files in pushed

Change-Id: I54f1f69edff19404ecec4f09f21e4ba0051a0b1c
8 files changed