* add onPreResponse interceptor
* use onPreResponse interceptor to add license sign
* expose registerPreResponse to plugins
* refresh for license update get the most fresh license
* license plugin injects own header for signature: 'kbn-license-sig'
* add integration tests for license type and license header
* switch config to duration
* don't run interceptor on anon paths. add tests
* add functional tests for licensing plugin
* regen docs
* fix test in security due to updated mocks;
* update snapshots accoring to new mock implementation
* migrate license expired banner to NP
* add readme for the licensing plugin
* remove outdated import. licensing has separate functional tests
* add tag for test to run on CI
* regen docs
* Update x-pack/plugins/licensing/README.md
Co-Authored-By: Josh Dover <me@joshdover.com>
* update tests