for now, nowhere, but I'll clean up the easybuild-easyconfigs unit tests to use this, for one

I didn't consider using it in other places, and I wonder whether it's worth the effort.
I guess it would result in a cleanup (e.g. we would be able to drop the `build_specs` named parameter to `EasyBlock`), but I'm not sure how big the effort would be to clean things up (although I would guess it would be minor).

How strongly do you feel about cleaning things up to only pass parsed easyconfigs to the `EasyBlock` constructor?

BTW: deprecating it is pretty useless, I consider this 'internal' API.