[Docs] Creates Developer docs GH page code

[ashwin-pc]

Description

Uses Docsify to generate documentation liks that expose Readme's within the OSD repo as HTML.

The GH Pages running on my local fork: https://ashwin-pc.github.io/OpenSearch-Dashboards/docs/index.html#/

Issues Resolved

Screenshot

Testing the changes

Check List

• [ ] All tests pass
  • [ ] yarn test:jest
  • [ ] yarn test:jest_integration
• [ ] New functionality includes testing.
• [ ] New functionality has been documented.
• [ ] Update CHANGELOG.md
• [x] Commits are signed per the DCO using --signoff