Use the default request items across CMEW

[ehogan]

#349 minimises duplication of the CDDS default request items within the configure_standardise task. However, some values defined in the default request are hard-coded in other places, e.g. project, exp and activity in CMEW/app/configure_for/bin/update_recipe_file.py.

Questions:

• From a documentation perspective (i.e. as mentioned in Refactor environment variables in Python modules #363), would it be worth separating the request into common_values and values_for_request_file? 🤔
• Are there other instances in CMEW where similar values are hard-coded?
• For configure_standardise it made sense for the default request items to be stored in a cfg file. For the "common" values, would it be worth considering data classes (as mentioned in Refactor environment variables in Python modules #363)?