[management, reverse proxy] Add reverse proxy feature (#5291)

* implement reverse proxy


---------

Co-authored-by: Alisdair MacLeod <git@alisdairmacleod.co.uk>
Co-authored-by: mlsmaycon <mlsmaycon@gmail.com>
Co-authored-by: Eduard Gert <kontakt@eduardgert.de>
Co-authored-by: Viktor Liu <viktor@netbird.io>
Co-authored-by: Diego Noguês <diego.sure@gmail.com>
Co-authored-by: Diego Noguês <49420+diegocn@users.noreply.github.com>
Co-authored-by: Bethuel Mmbaga <bethuelmbaga12@gmail.com>
Co-authored-by: Zoltan Papp <zoltan.pmail@gmail.com>
Co-authored-by: Ashley Mensah <ashleyamo982@gmail.com>

proxy/Dockerfile.multistage

@@ -0,0 +1,37 @@
+FROM golang:1.25-alpine AS builder
+WORKDIR /app
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY client ./client
+COPY dns ./dns
+COPY encryption ./encryption
+COPY flow ./flow
+COPY formatter ./formatter
+COPY monotime ./monotime
+COPY proxy ./proxy
+COPY route ./route
+COPY shared ./shared
+COPY sharedsock ./sharedsock
+COPY upload-server ./upload-server
+COPY util ./util
+COPY version ./version
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o netbird-proxy ./proxy/cmd/proxy
+
+RUN echo "netbird:x:1000:1000:netbird:/var/lib/netbird:/sbin/nologin" > /tmp/passwd && \
+    echo "netbird:x:1000:netbird" > /tmp/group && \
+    mkdir -p /tmp/var/lib/netbird && \
+    mkdir -p /tmp/certs
+
+FROM gcr.io/distroless/base:debug
+COPY --from=builder /app/netbird-proxy /usr/bin/netbird-proxy
+COPY --from=builder /tmp/passwd /etc/passwd
+COPY --from=builder /tmp/group /etc/group
+COPY --from=builder /tmp/var/lib/netbird /var/lib/netbird
+COPY --from=builder --chown=1000:1000 --chmod=755 /tmp/certs /certs
+USER netbird:netbird
+ENV HOME=/var/lib/netbird
+ENV NB_PROXY_ADDRESS=":8443"
+EXPOSE 8443
+ENTRYPOINT ["/usr/bin/netbird-proxy"]