Import Oa subjects without explicit import in the recipe

[lorenaqendro]

Description

Understand which oa subject is needed so the user does not need to include it as a datasource at all in the recipe. Good idea, but why are the oa subjects different to the other subjects to not be imported automatically? Needs to be explained carefully in the documentation. Might still be misleading if my subject is trafficCount for example with the geo match rule of lsoas.