Migrate to jaegertracing org

[yurishkuro]

Per jaegertracing/jaeger#409

• Move the repo
• Re-register the repo with Travis
• Re-register the repo with Coveralls/CodeCov
• Re-encrypt credentials
• Update the links to badges in the README
• Add DCO file
• Add sign-off checker bot
• Update CONTRIBUTING instructions to require sign-off
• Update to Apache license
  • Replace LICENSE file
  • Update CONTRIBUTING instructions and references to license in the README
  • Update the existing license headers (keep Uber copyright)
  • Update the check-license script (new files get The Jaeger Authors copyright)

[yurishkuro]

The license check is currently disabled:

$ m package.json | g check-license
58:    "check-license": "./node_modules/.bin/uber-licence --dry",
64:    "lint-ci": "npm run lint && echo '# TODO: ADD npm run check-license'",

The uber-licence module only applies MIT license afaict, we need to remove it from package.json and find a replacement.