add ENGN image

[fernandogelin]

@singhsaluja bringing the cantera discussion here. Instead of creating a new stage you can do something like this. I think this will be more consistent with the SQLITE install option.

ARG CANTERA #add this with other args at the top.

RUN if [ "$CANTERA" = "true" ] ; then \
    conda install --name ${CLASS} -y -c cantera cantera && \  #make sure you install in the class environment
    conda clean --all -f -y ; \
    fi 

then add an extra env in the workflow files:

env:
  CLASS: engn1120
  TARGET: base
  CANTERA: true