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/Dockerfile.parts/mimalloc/Dockerfile.alpine

@@ -0,0 +1,10 @@
+FROM alpine:latest as mimalloc
+
+RUN apk update && apk upgrade && apk --no-cache add gcc g++ libc-dev make cmake git
+RUN git clone https://github.com/microsoft/mimalloc && \
+  cd mimalloc && \
+  mkdir -p out/secure && \
+  cd out/secure && \
+  cmake -DMI_SECURE=ON ../.. && \
+  make && \
+  cp ./libmimalloc-secure.so ../../../libmimalloc.so