hadrian: Drop --configure support

Hadrian's --configure support has long been a point of contention. While it's convenient, it also introduces a fair bit of implementation complexity and quite a few non-trivial failure modes (see #19804 (closed), 17883, and #15948 (closed)). Moreover, the feature is actively misleading to the user: ./configure is the primary means for the user to inform the build system about the system environment and in general will require input from the user.

This commits removes the feature, replacing the flag with a stub message informing the user of the deprecation.

Closes #20167 (closed). Closes #19804 (closed).