Ability to setDebugInfo() on StageConfig, to override the dynamic debug info

[stolsvik]

When context.reply(..) is invoked by MatsImpl due to lastStage(..) or SpringConfig's lambda handling of same (both @MatsMapping and @MatsClassMapping), then we do not get any sane dynamic debug info. (Check what happens on next and request for SpringConfig @MatsClassMapping)

Also evaluate such debug info for the "creation point". Maybe always set creation point (which gives ability to also display this in introspection) - and then check for the dynamic info whether it works out, and if not, use the creation point.

[stolsvik]

Fixed at 2022-02-22, git 3486673, named setOrigin(..)