Clean-up and Publish the LSP package

[rhamzeh]

We have an LSP at https://github.com/openfga/vscode-ext/blob/main/server/package.json

We'd like to publish it so that community members building integrations for other IDEs (e.g. https://github.com/hedengran/fga.nvim) can use it.

We need to:

• Rename the package to @openfga/lsp-server
• Create a README.md file in ./server that describes the LSP
• Link to documentation and examples around how to integrate and make use of the LSP
• Setup the workflow to publish this to npm

[aaguiarz]

@hedengran we are trying to make it easier :)