Build docker container

Builds a Debian Bookworm (slim) docker container with Admarus pre-built inside it, and the OpenSSL dynamic libraries.

Run with:

```sh
docker run --network=host ghcr.io/Mubelotix/admarus:master \
  --ipfs-rpc=http://host.docker.internal:5001 \
  --external-addrs=/ip4/$(curl -s https://api.ipify.org)/tcp/4002 \
  --external-addrs=/ip6/$(curl -s https://api64.ipify.org)/tcp/4002 \
```

fixes #97

.github/workflows/publish-docker.yaml

@@ -0,0 +1,46 @@
+name: Publish container
+
+on:
+  push:
+    branches:
+      - master
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

Dockerfile

@@ -0,0 +1,23 @@
+FROM rust:1-slim-bookworm as build
+
+RUN apt-get update && apt-get install -y pkg-config libssl-dev && apt-get clean
+
+WORKDIR /usr/src/admarus
+COPY . .
+
+RUN cd daemon && \
+    cargo build --release && \
+    mv ../target/release/admarusd /usr/local/bin/admarusd && \
+    cd ../../ && \
+    rm -rf admarus
+
+FROM debian:bookworm-slim
+
+RUN apt-get update && apt-get install -y libssl ca-certificates && apt-get clean
+
+COPY --from=build /usr/local/bin/admarusd /usr/local/bin/admarusd
+
+EXPOSE 4002
+EXPOSE 5002
+
+ENTRYPOINT ["/usr/local/bin/admarusd"]