DD4Hep DT Geometry Builder: implement comments

[fabiocos]

In the review of #25842 a list fo comments was proposed to @ianna by @Dr15Jones and @cvuosalo . We agreed to merge the PR to simplify further work, and address all the comments in a second step. This issue should serve as a reminder for the follow-up.

[cmsbuild]

A new Issue was created by @fabiocos Fabio Cossutti.

@davidlange6, @Dr15Jones, @smuzaffar, @fabiocos, @kpedro88 can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[fabiocos]

assign geometry

[cmsbuild]

New categories assigned: geometry

@Dr15Jones,@cvuosalo,@ianna,@civanch,@mdhildreth you have been requested to review this Pull request/Issue and eventually sign? Thanks

[ianna]

@cvuosalo and @slomeo - please, have a look at the comments in #25897. They have to be addressed. One in particular: using smart pointers.

[ianna]

+1

done

[cmsbuild]

This issue is fully signed and ready to be closed.