Dockerfile Parts (#428)

* De-duplicate Dockerfiles by using a bash file to concatenate common parts

Resolves #375.

Dockerfiles are still committed to the repo to avoid a dependency on bash.

* Add a CI job to confirm the committed dockerfiles are the currently generated ones

* Create dedicated Dockerfiles per processor network

Ensures the compromising of network-specific dependencies doesn't lead to a
compromise of the build process for all processors.

* Dockerfile corrections

* Correct call to build processor Docker image in tests/processor

orchestration/processor/Dockerfile.processor.end

@@ -0,0 +1,15 @@
+# Install ca-certificates
+RUN apt install -y ca-certificates
+
+# Switch to a non-root user
+RUN useradd --system --create-home --shell /sbin/nologin processor
+USER processor
+
+WORKDIR /home/processor
+
+# Copy the Processor binary and relevant license
+COPY --from=builder --chown=processsor /serai/bin/serai-processor /bin/
+COPY --from=builder --chown=processsor /serai/AGPL-3.0 .
+
+# Run processor
+CMD ["serai-processor"]