Move github examples into services/github (#2309)

lib/all-badge-examples.js

services/github/github-commit-activity.service.js

services/github/github-commit-status.service.js

services/github/github-commits-since.service.js

services/github/github-contributors.service.js

services/github/github-downloads.service.js

services/github/github-followers.service.js

services/github/github-forks.service.js

services/github/github-issue-detail.service.js

services/github/github-issues.service.js

services/github/github-languages.service.js

services/github/github-last-commit.service.js

services/github/github-license.service.js

services/github/github-manifest-version.service.js

services/github/github-release-date.service.js

services/github/github-release.service.js

services/github/github-repo-size.service.js

services/github/github-search.service.js

services/github/github-size.service.js

services/github/github-stars.service.js