R1:aa6e788f3666

Mark "v3" API methods as stable; mark obsoleted methods as "Frozen"

Summary:
Ref T12074. The "v3" API methods (`*.search`, `*.edit`) are currently marked as "unstable", but they're pretty stable and essentially all new code should be using them.

Although these methods are seeing some changes, almost all changes are additive (support for new constraints or attachemnts) and do not break backward compatibility. We have no major, compatibility-breaking changes planned.

I don't want to mark the older methods…