Separate "server" code from vscode extension

[waynehamadi]

Everything that doesn't use the vscode package should go on the server side, in order to get a light client and put all the logic in the server.

You'll get inspiration from the marvelous vscode extension "writer" from mintlify: See the code here: https://github.com/mintlify/writer

❤️ @handotdev and @hahnbeelee