Added Jenkins pipeline
Added initial Jenkinsfile for CI/CD.
It includes the following stages:
- installing NPM packages
- veryfing src and test with eslint
- running Jest tests
- publishing HTML reports
Other stages are defined so they can be implemented later.
Additional changes:
- Added linting for tests to disallow tests with .only. Additionally configured the src and tests linters to avoid console.log and debugger statements.
- Added npm run test:report script that generates coverage & test results reports which can be used in Jenkins. Configured second Jest config only for reporting that extends the base one.