[adapters] Use an adapter for serializing entities to a bare python structure
which may be used for e.g. JSON export or other and allow to have different
serializations for each entity types.
Closes #6378035
for table, column in [
('transactions', 'tx_time'),
('tx_entity_actions', 'tx_uuid'),
('tx_relation_actions', 'tx_uuid')]:
repo.system_source.create_index(session, table, column)
commit()