Make Gizmo the default member accessor

[triceo]

• Detect when we can enable Gizmo by trying a super-quick bytecode manipulation.
• If possible, enable Gizmo; otherwise keep Reflection.
• Log to TRACE what the effective method is.
• Remove any means of the user choosing the method for themselves.
• Remove AutoDiscoverMemberType and do the right thing instead. (This may lead to quite some simplification in the accompanying code.)

The code around member accessors and how they are built is also quite complex, on account of Quarkus choosing a completely different code path. The factories are a bit of a mess. Bonus points if it could be simplified.

[Christopher-Chianelli]

Done by #2123