Stop using cargo internal API, too complicated. Switch to programmatically parsing metadata output. Add CI (untested, probably doesn't work), create dockerfile

Dockerfile

@@ -0,0 +1,15 @@
+FROM docker.io/rust:1.87.0 AS build
+
+WORKDIR /app
+
+COPY . .
+
+RUN cargo build --release --bin harmony_composer
+
+FROM docker.io/rust:1.87.0
+
+WORKDIR /app
+
+COPY --from=build /app/target/release/harmony_composer .
+
+ENTRYPOINT ["/app/harmony_composer"]