Feed CMEW's model_id through to ESMValTool recipe

[alistairsellar]

configure_for is not making use of model_id provided by CMEW. At the moment this is OK because it matches the model ID in the recipe, but this will not always be the case.

Definition of done:

• The esmvaltool recipe that is created by configure_for contains the model_id that the user provides to CMEW.
• (Assuming this issue is tackled after Compare two model development runs in a single run of CMEW #259 is merged) the same should apply for both the model_id of both the test and reference runs.