Feat: Add debug build process and Dockerfile

Introduced a new Dockerfile.debug to support building a debug version of the application. Updated the GitHub Actions workflow to include steps for building and pushing the debug image to the container registry. This enables enhanced debugging and testing capabilities for the application.

Signed-off-by: Christian Roessner <c@roessner.co>

.github/workflows/docker-features.yaml

@@ -34,3 +34,13 @@ jobs:
           tags: |
             ghcr.io/${{ github.repository_owner }}/nauthilus:dev
           outputs: type=image,name=target,annotation-index.org.opencontainers.image.description=Multi purpose authentication server
+
+      - uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: ./Dockerfile.debug
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: |
+            ghcr.io/${{ github.repository_owner }}/nauthilus:dev-dbg
+          outputs: type=image,name=target,annotation-index.org.opencontainers.image.description=Multi purpose authentication server

Dockerfile.debug

@@ -0,0 +1,37 @@
+FROM --platform=$BUILDPLATFORM golang:1.23-alpine3.20 AS builder
+
+LABEL org.opencontainers.image.authors="christian@roessner.email"
+LABEL org.opencontainers.image.source="https://github.com/croessner/nauthilus"
+LABEL org.opencontainers.image.description="Multi purpose authentication server"
+LABEL org.opencontainers.image.licenses=GPL3
+LABEL com.roessner-network-solutions.vendor="Rößner-Network-Solutions"
+
+WORKDIR /build
+
+COPY . ./
+
+# Set necessarry environment vairables and compile the app
+ENV CGO_ENABLED=0
+RUN apk add --no-cache build-base git
+
+RUN cd server && go build -mod=vendor -tags="register2fa" -ldflags="-s -X main.version=dev-dbg" -o nauthilus .
+RUN cd docker-healthcheck && go build -mod=vendor -ldflags="-s" -o healthcheck .
+RUN cd contrib/smtp-server && go build -mod=vendor -ldflags="-s" -o fakesmtp .
+RUN cd contrib/imap-server && go build -mod=vendor -ldflags="-s" -o fakeimap .
+
+RUN addgroup -S nauthilus; \
+    adduser -S nauthilus -G nauthilus -D -H -s /bin/nologin
+
+RUN apk --no-cache --upgrade add ca-certificates bash curl
+
+# set up nsswitch.conf for Go's "netgo" implementation
+# - https://github.com/golang/go/blob/go1.9.1/src/net/conf.go#L194-L275
+RUN echo 'hosts: files dns' > /etc/nsswitch.conf
+
+ENV TERM=xterm-256color
+
+EXPOSE 8180
+
+USER nauthilus
+
+CMD ["/build/server/nauthilus"]