Doc generation fix

[Shreyas-vgr]

Doc generation fix

Description

Fixed typedocs generation bugs and provided an npm run docs command to generate api_docs. Also removed lerna gulp and travis.yml dependencies since we have migrated to GitHub actions.

Testing

Generated the api_docs and verified all ts files being generated.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [x] Docs(Add new document content)
• [ ] Translate Docs(Translate document content)

Checklist

• [x] My code follows the code style of this project
• [x] My change requires a change to the documentation
• [x] I have updated the documentation accordingly
• [x] I have read the README document
• [ ] I have added tests to cover my changes
• [x] All new and existing tests passed
• [x] My commit message follows Conventional Commit Guideline

License

• [x] I confirm that this pull request can be released under the Apache 2 license