feat: add Dockerfile for Rabbit.go server build and deployment

- Create a multi-stage Dockerfile to build the Rabbit.go application using Go 1.24.0 on Alpine
- Set up the application to run in a distroless environment for minimal footprint
- Expose necessary ports for the tunnel server and API

Author: theboringhumane

server/Dockerfile

@@ -0,0 +1,17 @@
+FROM golang:1.24.0-alpine AS builder
+
+WORKDIR /app
+
+COPY . .
+
+RUN go build -ldflags="-s -w" -o rabbit.go main.go
+
+FROM gcr.io/distroless/static-debian12:latest as runner
+
+COPY --from=builder /app/rabbit.go /usr/local/bin/rabbit.go
+
+# 9999 is the tunnel server port
+# 3422 is the API port (never expose this port to the internet)
+EXPOSE 9999 3422
+
+ENTRYPOINT ["/usr/local/bin/rabbit.go", "server", "--bind", "0.0.0.0", "--port", "9999", "--api-port", "3422"]