core: Add a few TODOs for Cutelyst2 and improve docs
core: Add a few TODOs for Cutelyst2 and improve docs

simonaw/cutelyst,cutelyst/cutelyst,simonaw/cutelyst,buschmann23/cutelyst,cutelyst/cutelyst,buschmann23/cutelyst,cutelyst/cutelyst,buschmann23/cutelyst