Allow the worker to be launched with Slurm

.arkindex.yml

@@ -7,6 +7,7 @@ workers:
     type: extractor
     docker:
       build: Dockerfile
+      command: worker-init-elements
     user_configuration:
       chunks_number:
         title: Number of chunks to split workflow into after initialisation

Dockerfile

@@ -14,5 +14,3 @@ RUN pip install . --no-cache-dir
 # Add archi local CA
 RUN curl https://assets.teklia.com/teklia_dev_ca.pem > /usr/local/share/ca-certificates/arkindex-dev.crt && update-ca-certificates
 ENV REQUESTS_CA_BUNDLE /etc/ssl/certs/ca-certificates.crt
-
-CMD ["worker-init-elements"]