* 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
The lack of locking the connection when making an authenticated request, which
is actually two sequential requests, risked another caller making a request in
between, invalidating the state.
Now, only unauthenticated connections share a connection object.
