Factoring deduplication

[d-r-q]

Currently when graph with different persisted objects for the same entity (gid + state) is factorized, eavs of the entity is duplicated. This is due to internal implementation of EntityGraphFactoring - it keeps eavs in map obj -> List and to produce total eavs list it's just returns concatenation of the lists.

If the entity has unique attribute, it leads to unique constraint violation.

Redesign EntityGraphFactoring implementation to fix this issue