PLFM-2043: fix migration of serialized Evaluation objects
Merge pull request #560 from bkng/release-4

PLFM-2043: fix migration of serialized Evaluation objects
PLFM-2043: switch to flat columns for new Evaluation fields
test fix
Merge pull request #562 from bkng/release-4

PLFM-2043: switch to flat columns for new Evaluation fields
Merge branch 'release-4' into develop