Add the ability to customize the built in fields

[mirai-ux]

There should be an ability to remove the built in fields, like the Definition and Word fields. You should also have the ability to change the order of them, as well as the custom ones. Renaming would also be very convenient. I use custom fields for my anki workflow and it's quite annoying that a major part of my screen is covered up by empty Definition and Word fields. Adding a Reading field also screws with the order of operation that I have set up for myself