Add debuginfo build target

In the webinar we are currently producing on debugging openssl
applications, we talk about ways to allow debugable binaries without
having to ship all the debug DWARF information to production systems.

Add an optional target to do that DWARF separation to aid users

Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25174)