PromQL language support for VS Code

Prometheus Extension for VS Code based on the PromQL Language Server.

Trying out the extension

1. Download the latest release binary from the releases page and install it with

code --install-extension vscode-promql-<version>.vsix

2. Restart VS Code
3. If you want to get metadata from a Prometheus server, go to the Extensions -> PromQL section in the VS Code settings and set the URL of the server in the field Prometheus URL
4. Open some of the files in /src/test/testfiles/promql and try editing them.

If you don't trust the release binary you can of course also build it yourself using the Makefile.