Add lsif-typescript documentation

[olafurpg]

There is currently no documentation for lsif-typescript. We should update the Sourcegraph documentation to replace lsif-node with lsif-typescript https://docs.sourcegraph.com/code_intelligence/how-to/index_a_typescript_and_javascript_repository#manual-indexing

• Update docs.sourcegraph.com
• Blog post announcement (under review)
• Add README
• Add example GitHub Action for lsif-typescript repo
• Archive lsif-node repo Add deprecation notice for this repo lsif-node#229
• Update readme to include migration instructions from lsif-node

[olafurpg]

WIP pull request https://github.com/sourcegraph/sourcegraph/pull/34097