AthenaCommon+AthenaConfiguration: remove hard dependencies on legacy configurables
In order to remove hard dependencies on the legacy configurables in CA jobs, only import them when needed. Ultimately, this will make it easier to fully remove the legacy configurable classes.
As a first step, I am thinking to forbid their usage/import in CA jobs as this would have helped discovering bugs like !68679 (merged) more easily. But even that requires a bit more cleanup.