Move source to csnx

[sndrs]

relies on

• [ ] https://github.com/guardian/source/issues/1576
• [x] https://github.com/guardian/CSTI-team/issues/2

[tjsilver]

• [x] Refactor Storybook in Source to make a more standard implementation
• [x] Migrate src folder and changelog files from
  • [x] source-foundations
  • [x] source-react-components
  • [x] source-react-components-development-kitchen
  • [x] eslint-plugin-source-foundations
  • [x] eslint-plugin-source-react-components
• [x] Decide on whether to migrate git history
• [ ] ~Migrate git history if applicable~ (decided to wait and see if we need to do this)
• [x] Do we want to migrate the central Source readme? Where do we surface a link to the storybook etc..

[tjsilver]

Migration steps

• [x] Raise PR
• [ ] Fix review comments
• [ ] Disable Source deployments in CSNX
• [ ] Merge PR
• [ ] Test
  • [ ] CI/CD
  • [ ] NPM
  • [ ] Storybook
  • [ ] Documentation
• [ ] Code freeze
  • [ ] Choose a day for final transfer
  • [ ] Draft email to department
  • [ ] Merge existing PRs into Source repo
• [ ] Make final copy of Source and changelogs
• [ ] Archive Source repo
• [ ] Enable Source deployments in CSNX
• [ ] Defrost code