feat(build): add Docker support for gitks application

- Add .dockerignore file to exclude unnecessary files from Docker build context
- Create multi-stage Dockerfile with rust builder and debian runtime stages
- Configure environment variables for host and port settings
- Set up proper EXPOSE and ENTRYPOINT instructions
- Optimize build with cargo release and binary stripping
- Install only required dependencies in production stage

Dockerfile

@@ -0,0 +1,22 @@
+FROM rust:1.96-bookworm AS builder
+
+WORKDIR /app
+COPY . .
+
+RUN cargo build --release --bin gitks && \
+    strip target/release/gitks
+
+FROM debian:bookworm-slim
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends git ca-certificates && \
+    rm -rf /var/lib/apt/lists/*
+
+COPY --from=builder /app/target/release/gitks /usr/local/bin/gitks
+
+ENV GITKS_HOST=0.0.0.0
+ENV GITKS_PORT=50051
+
+EXPOSE 50051
+
+ENTRYPOINT ["gitks"]