Migrate event command list to model/view framework #5
Description
The current way of interfacing with the event command list is by connecting slots. This is difficult to read and doesn't allow for granular control of the underlying event, needing ugly workarounds for things like the Play BGM/SE commands, which would defer the data to an intermediary picker. The way that the list is updated is also extremely flaky.
Switching to the model/view framework would make updating individual and grouped items significantly easier, more flexible and less error prone. It'd also make the relation between commands and the command widgets clearer in code. Finally, we'd get to customize the view to add QOL features like line numbers.