KCINFR-979: making s2s error messages end user maintainable
KCINFR-979: fixing uniqueness rule, changing locking key, adding a sort order
KRACOEUS-6955: code review comments, also fixing another maintenance situation.
Merge pull request #485 from leoherbie/s2s_error

KCINFR-979: making s2s error messages end user maintainable