[Rebuilt] - Fix the possible confusion between title and token properties.

[piconti]

As pointed out by @simon-clematide and described in this issue in impresso-schemas, currently two properties of the rebuilt content items are named "t"; the CI title and the CI tokens.
While these don't reside at the same hierachy level, preventing too many confusions, it's best not having two properties with the same name within one schema.

Ideally, this is done during/for the next ingestion, fixing previous data too.