chore: dual publish to npm

[psteinroe]

this pr set ups dual publish to the @postgres-language-server namespace. also:

• after seeing pgls in the wild I decided we should name the binary postgres-language-server
• we now copy the README.md into each package when releasing
• added a deprecation notice to the postgestools packages' readme

[juleswritescode]

i just committed a suggestion here, please make sure that checks out 👍🏻
rest LGTM!