Refactor the codebase

[tetlowgm]

While I've been working to revamp the codebase for OpenSSL 3.0 (which actually works up to OpenSSL 3.4 as well), there are some opportunities to refactor the codebase to reduce copy/pastes and abstract some of the OpenSSL pieces a bit further. Chugging in a nearly 6k lines in sslscan.c, it might also serve to break it apart into multiple files as well. @rbsec, If I were to undertake that effort, would there be objection to accepting that? I would of course be open to any review and feedback on the approach, but I want to ask before I sink some effort into it. Thanks!