Move mouse handling back to delegates
Due to Pane being a QtControl it is impossible to have some mouse handling in delegates and some handled outside the TableView. We need to revert back to the original design and leave the mouse handling in the delegates.
This effectively reverts commit b120af5c.
It was tidied to move mouse handling up to a common ancestor of the item
This makes delegate code cleaner compared to a common background for two reasons:
- We can access the root attached properties
- We can set a Kirigami.Theme that gets inherited by the delegates, without needing the cyclic flow of information
This should help with a move to move BaseTableView to frameworks eventually