When loading revision slots from the new MCR schema, slot role names
and content model names need to be resolved. Doing so programmatically
based on an in-memory cache avoids having to join against two additional
table every time we load slot meta-data.
This relies on NameTableStore, which was designed for exactly this use
case.
Bug: T198561
Change-Id: Ic005931b669f9d0173ef47ac17331d44fb1141ca
NOTE: this changes the numeric values of the MIGRATION_XXX constants!
Order is preserved.
Bug: T197619
Change-Id: I16db7dd5799ab98c1cb12e7cd1e0b2da83b366fc